Move error checking to onMouseUp events instead of on all blockly workspace changes.

Change-Id: I530a6e34f196d3722d3a50b9555d6dc269943d7a
fix for Twitter API change. Only SSL traffic allowed

Change-Id: I76047e13852ba4112b324014b488b6c0a08358ed
fix for collapsed blocks swallowing other blocks

Change-Id: I71c996463e8dafbb76955ea08da4bca0a3385d9e
Fix to initial lag in drag in large projects and also issue 667.

Removing the onchange handler in lexical_variable_get and lexical_variable_set
eliminates the remaining delay in starting a block drag in large projects.
It also fixes issue 667 in which copying variable setters and getters out
of scope changed the current names to the empty string. Now the names remain,
but the getter/setter block has a red error triangle.

This does *not* improve many other nasty lags involving large projects:
* loading large projects is numbingly slow
* mouse-up on a moved block is very slow because of an unexpectedly large
  number of render calls
* displaying a drop-down list for event-handler component or variable
  is unexpectedly slow.

Change-Id: If06a3011d5b31fc5308fc33e99c2a0adb2fdb160
Add documentation on barcode scanner to reference docs

Change-Id: Iff34a60853724dc43b71298fa6b628278dc404ca
Update Splash Screen in Companion

Change-Id: I7bdf1ec8069e6378c55b1b2a37b903f36b108f48
Fix a NPF in the NearField Component.

Fix a NPF reported via Acra and the Play Store.

Change-Id: Icbac7eb9e71880b1624857c45ee1ad514a39ed4c
Make half-created files empty.

File creation is a two-step process, first the file is created and
then it is populated with data. If the second step fails, the file is
left in an inconsistent state which damages the containing
project. This change causes half-created files to return as empty.

Change-Id: I09147e8eb389b249dde57862d07063434df4f0a3
Update Companion Version to 2.12ai2zx1

Change-Id: Ic0a1e0914eafe10788c96ce8d6d908f91fa6a781
Merge branch 'master' into localserver