Upgrade ESRI JSAPI

Update JS and CSS files to the latest versions provided by ESRI.
Note that the dojo resource for ResizeHandle.css is not available
at 3.11 but I did upgrade from 3.8 -> 3.10.

I encountered no framework or core issues, though other plugins may
need to make updates to be compatible

Fixes #279
Add framework method for downloading text

Plugins can now use app.downloadAsCsv and app.downloadAsPlainText
to initiate downloads of text files.