Add a unique build number to every build

SDK-readable via android.os.Build.INCREMENTAL

Change-Id: If9885adebe12a56b2b2e353285721be695bc411b
Kernel : Use Linaro 4.7.4 Toolchain

Change-Id: Iac0e1deb2f030b283c9dc858d290552b345d4689
Rom : Use -O3 for Optimization

Change-Id: I63db46028d7ed54a72e5b23ea58095778fc5c69d
Disable -Wunused-parameter

Change-Id: I4289c7d97d1d9694dd74f23d2e0fee07d2374e67