Update changelog for M7

...and M6 and M5...

Change-Id: I5f900e6e4ab4807491dbd783f69caae9792b3ab1
Revert "cm: Add some app-specific performance settings"

This reverts commit 34d5e908433ce79e1c7fbcb88cf1661a4adb1743.
Persist DPI across installs
Add OmniSwitch