Let the Companion Display Assets.

Arrange to fetch assets from the APK file in the Companion so it can
have a UI with images etc. Add a function to the PhoneStatus block
used to declare that the UI is loaded and assets should now be loaded
from the SD Card (because they would be loaded by the App being
developed!).

Change-Id: Ib2f407d97db9ac2fba7c7e242e3a974f2590b5f2
Added help links for component blocks. Also updated the links for builtin blocks to reflect the upcoming url change.

Change-Id: Iadcbd37a1be5c70d5b880186d5d3be4178b113a9
Merge branch 'master' into newblocks

Change-Id: If9a5ac8ae9861627f372830bb922eb7c6b5bb0de