Fix language version ungrader for change to camera component

Change-Id: I81f7873d0c44c85871cc09e73b9d0272af35b0be
Fix crash reulsuting from trying to create a canvas bitmap with width or
height equal to zero.   This is apparently an order of events issue related to
width or height being specified as FILL_PARENT.  This is trac issue 631

Change-Id: I29c88ee0a9701c92505800ff0f117f45d17e308f
Update Title of Connection Failure Message

Change-Id: Ic9461793d29b96732a79e1dbe8b52223ac15e2d2
Fetch information in bulk about projects.

Reduce the number of datastore api calls at startup when the meta data
about all projects is gathered. Three calls are reduced to one for
each project.

Change-Id: Ia257515e5c4e7d62c662c49f24ba68055c4e55fd
Provide a specific error message when rpc is incompatible

Change-Id: Id9f5ae4ef8f1d2fe0b69f3051cfa418f778abf7e
Increase the reliability of starting the Emulator

Increase the “ubergiveup” threshold to 8. Add the option for the user
to tell App Inventor to keep trying even after the ubergiveup
interval. Add an extra intent to start the Companion if it hasn’t
shown a response yet. This should increase the chances of the
Companion starting on very slow computers. Changed some timers
as well.

Minor change to the build environment so that versions are marked
“dirty” (in the Help->About Menu) if the system was built from a work
tree that has changes that are not yet committed in any branch.

Change-Id: I7bd42d36b3b005c2e072aad60b65afe555e8f2e1
Fix URL pointer to Help page for sensor components

Change-Id: I658540a00dc760c514a080071c7bf5128bce50e9
Only permit one session per user

Only permit one session per user. Newer sessions cause older sessions
to become read-only. Enforcement is controlled by a flag in
AppInventorFeatures.

Change-Id: Ie493b6477473dc8d9377690a044a9fa012e2f27c