Remove trailing spaces
Seperate requirement installation from GYP defines
Merge release/debug build functions

By setting WEBRTC_DEBUG=true to build in debug mode.
Remove $DEFINES environement variable.
Support building for Android x86
Copy all lib files (.so/.jar) at once
Keep old builds
Do not sync before every build.

Use `get_webrtc` to clone the source.
Update README.md
Merge pull request #15 from wancw/feature/android_x86

Support Android x86 ABI