changes text in Error and Warning bubbles to be selectable

Change-Id: I5cd838c470474442f0f2f6f73501430ff4f9b9f2
matching component documentation URLs with values in _messages file

Change-Id: Ibfdb1f9bf426fd62b67043e8610d46b72ac6d21f
adds glass panel for popup menus so that they auto close when clicking on blocks editor

Change-Id: I5998908f55b09db56f18ad7e78100e75976c4b3b
Merge branch 'master' of https://github.com/mit-cml/appinventor-sources