* API core for model downloader
* initial basic dialog for missing models
* app.ts handling for missing models
* don't explode if getModels is a 404
* actually track downloads in progress
* overall pile of improvements to the missing models view
* minor fixes
* add setting to disable missing models warning
* temporarily remove 'models' entry from default graph
to avoid missing model dialog causing issues. Also because ckpt autodownloading shouldn't be allowed
* swap the url to a title
* add model directory to display
* match settingStore commit
* check setting before scanning models list
ie avoid redundant calcs when setting is disabled anyway
