This copies the platform-specific emulator modules from sdk.git into
development.git/tools/emulator/system/. Note the use of guard variables
to prevent clashes when the original modules are still in the tree.
The goal is to submit this and https://review.source.android.com/#change,21737,
then later remove the modules from sdk.git when we move the internal sdk branch
to the appropriate tools_rXXX branch.
Change-Id: I762d0efb72d93a935d96c4549f36029c258c3ef9
