Add GridLayout as a support project library.

The library is distributed as a project containing a single jar and resources
but the jar file is built by the Android build system in order to target the
current API.
The code also relies on the R class being generated, which is currently done
manually. The build system uses an intermediary library to compile the R class
so that it doesn't get packaged in the final jar file (same behavior as
compiling the library project with the SDK).

Change-Id: I36ce97d875f2efbb50cca665e9fd0e668f5ba837
14 files changed
tree: 9dadc24ea8eb2830ab41218663225fa0091010e9
  1. v13/
  2. v4/
  3. v7/
  4. volley/