Revert "Switch to GCC 4.7"

This reverts commit 9648358ffdd61f6c0a7ae19fda811f91e814c81d.
Freedom to use any GCC Version

Does not break current builds as GCC 4.6 is set as the default version.
If you want to use a newer version add a flag in the BoardConfig for
your device as follow

TARGET_GCC_VERSION := <version-to-use>
eg
TARGET_GCC_VERSION := 4.7

and

TARGET_USE_O3 := <value>
eg
TARGET_USE_O3 := true

Change-Id: Iae44849e28add59bc1810b029fa575bff9c24e50

Conflicts:
CleanSpec.mk
Fix derp

Change-Id: I472c26413ef314d32c0427db42af9f1b68506d85
Optimize for Size

Change-Id: Id8e9ab078dbcedd98d05a4116dddcdc4a2e4dfa6
Some enhancements

Change-Id: Ib22383c88cd3ccae6a8ded85cc16606ac2674e06