Defined a new level-1d operation: shiftd.

Details:
- Defined a new level-1d operation called 'shiftd', including object and
  typed APIs. This operation adds a scalar value to every element along
  an arbitrary diagonal of a matrix. Currently, shiftd is implemented in
  terms of the addv kernel. (The scalar is passed in as the x vector
  with an increment of zero.)
- Replaced ad-hoc usage of setd and addd (after creating a temporary
  matrix object) with use of shiftd, which is much more concise, in
  various test driver files in the testsuite. Similar changes were made
  to the standalone test drivers and the example code.
- Added documentation entries in BLISObjectAPI.md and BLISTypedAPI.md
  for bli_shiftd() and bli_?shiftd(), respectively.
- Added observed object properties to level-1d documentation in
  BLISObjectAPI.md.

docs/BLISObjectAPI.md

@@ -597,7 +597,7 @@ Notes for interpreting function descriptions:
   * **[Level-1v](BLISObjectAPI.md#level-1v-operations)**: Operations on vectors:
     * [addv](BLISObjectAPI.md#addv), [amaxv](BLISObjectAPI.md#amaxv), [axpyv](BLISObjectAPI.md#axpyv), [axpbyv](BLISObjectAPI.md#axpbyv), [copyv](BLISObjectAPI.md#copyv), [dotv](BLISObjectAPI.md#dotv), [dotxv](BLISObjectAPI.md#dotxv), [invertv](BLISObjectAPI.md#invertv), [scal2v](BLISObjectAPI.md#scal2v), [scalv](BLISObjectAPI.md#scalv), [setv](BLISObjectAPI.md#setv), [setrv](BLISObjectAPI.md#setrv), [setiv](BLISObjectAPI.md#setiv), [subv](BLISObjectAPI.md#subv), [swapv](BLISObjectAPI.md#swapv), [xpbyv](BLISObjectAPI.md#xpbyv)
   * **[Level-1d](BLISObjectAPI.md#level-1d-operations)**: Element-wise operations on matrix diagonals:
-    * [addd](BLISObjectAPI.md#addd), [axpyd](BLISObjectAPI.md#axpyd), [copyd](BLISObjectAPI.md#copyd), [invertd](BLISObjectAPI.md#invertd), [scald](BLISObjectAPI.md#scald), [scal2d](BLISObjectAPI.md#scal2d), [setd](BLISObjectAPI.md#setd), [setid](BLISObjectAPI.md#setid), [subd](BLISObjectAPI.md#subd)
+    * [addd](BLISObjectAPI.md#addd), [axpyd](BLISObjectAPI.md#axpyd), [copyd](BLISObjectAPI.md#copyd), [invertd](BLISObjectAPI.md#invertd), [scald](BLISObjectAPI.md#scald), [scal2d](BLISObjectAPI.md#scal2d), [setd](BLISObjectAPI.md#setd), [setid](BLISObjectAPI.md#setid), [shiftd](BLISObjectAPI.md#shiftd), [subd](BLISObjectAPI.md#subd)
   * **[Level-1m](BLISObjectAPI.md#level-1m-operations)**: Element-wise operations on matrices:
     * [addm](BLISObjectAPI.md#addm), [axpym](BLISObjectAPI.md#axpym), [copym](BLISObjectAPI.md#copym), [scalm](BLISObjectAPI.md#scalm), [scal2m](BLISObjectAPI.md#scal2m), [setm](BLISObjectAPI.md#setm), [setrm](BLISObjectAPI.md#setrm), [setim](BLISObjectAPI.md#setim), [subm](BLISObjectAPI.md#subm)
   * **[Level-1f](BLISObjectAPI.md#level-1f-operations)**: Fused operations on multiple vectors:
@@ -771,6 +771,8 @@ Perform
 ```
 where `x` is a vector of length _n_, and `alpha` is a scalar.
 
+Observed object properties: `conj?(alpha)`.
+
 ---
 
 #### scal2v
@@ -788,6 +790,8 @@ Perform
 ```
 where `x` and `y` are vectors of length _n_, and `alpha` is a scalar.
 
+Observed object properties: `conj?(alpha)`, `conj?(x)`.
+
 ---
 
 #### setv
@@ -804,6 +808,8 @@ Perform
 ```
 That is, set all elements of an _n_-length vector `x` to scalar `conj?(alpha)`.
 
+Observed object properties: `conj?(alpha)`.
+
 ---
 
 #### setrv
@@ -856,6 +862,8 @@ Perform
 ```
 where `x` and `y` are vectors of length _n_.
 
+Observed object properties: `conj?(x)`.
+
 ---
 
 #### swapv
@@ -885,6 +893,8 @@ Perform
 ```
 where `x` and `y` are vectors of length _n_, and `beta` is a scalar.
 
+Observed object properties: `conj?(beta)`, `conj?(x)`.
+
 ---
 
 
@@ -908,6 +918,8 @@ void bli_addd
      );
 ```
 
+Observed object properties: `diagoff(A)`, `diag(A)`, `trans?(A)`.
+
 ---
 
 #### axpyd
@@ -920,6 +932,8 @@ void bli_axpyd
      );
 ```
 
+Observed object properties: `conj?(alpha)`, `diagoff(A)`, `diag(A)`, `trans?(A)`.
+
 ---
 
 #### copyd
@@ -931,6 +945,8 @@ void bli_copyd
      );
 ```
 
+Observed object properties: `diagoff(A)`, `diag(A)`, `trans?(A)`.
+
 ---
 
 #### invertd
@@ -941,6 +957,8 @@ void bli_invertd
      );
 ```
 
+Observed object properties: `diagoff(A)`.
+
 ---
 
 #### scald
@@ -952,6 +970,8 @@ void bli_scald
      );
 ```
 
+Observed object properties: `conj?(alpha)`, `diagoff(A)`.
+
 ---
 
 #### scal2d
@@ -964,6 +984,8 @@ void bli_scal2d
      );
 ```
 
+Observed object properties: `conj?(alpha)`, `diagoff(A)`, `diag(A)`, `trans?(A)`.
+
 ---
 
 #### setd
@@ -975,6 +997,8 @@ void bli_setd
      );
 ```
 
+Observed object properties: `conj?(alpha)`, `diagoff(A)`, `diag(A)`.
+
 ---
 
 #### setid
@@ -985,7 +1009,26 @@ void bli_setid
        obj_t*  a
      );
 ```
-Set the imaginary components of a matrix diagonal to a scalar `alpha`.
+Set the imaginary components of every element along the diagonal of `a`
+to a scalar `alpha`.
+Note that the datatype of `alpha` must be the real projection of the datatype
+of `a`.
+
+Observed object properties: `diagoff(A)`.
+
+---
+
+#### shiftd
+```c
+void bli_shiftd
+     (
+       obj_t*  alpha,
+       obj_t*  a
+     );
+```
+Add a constant value `alpha` to every element along the diagonal of `a`.
+
+Observed object properties: `diagoff(A)`.
 
 ---
 
@@ -998,6 +1041,8 @@ void bli_subd
      );
 ```
 
+Observed object properties: `diagoff(A)`, `diag(A)`, `trans?(A)`.
+
 ---