Make gcc 4.6 default and non O3

* to use gcc 4.7 add TARGET_GCC_VERSION := 4.7 to your board config
* to use O3 add TARGET_USE_O3

Change-Id: Ia4a00023c84cc21122bdf1c116e51a179ccabd8c
Add optimization paramater to lunch

When you run lunch you can see the optimizations enabled in your boradconfig.mk
Current options are TARGET_GCC_VERSION/TARGET_USE_O3/TARGET_USE_LINARO_STRING_ROUTINES

Change-Id: Ie2870165906129381fdc0c28fc13f26fbb11c22d
Graphite optimizatoin flags

Enable with use TARGET_USE_GRAPHITE
*currently expermental

Change-Id: I2126a86986c4f7eed7252ed40d860b2f74725afb