README: update to cm-10.2 branch

Change-Id: I340f994886c5e2cf365888103257697aeeaa875f
Signed-off-by: Rohan Mathur <rohanmathur34@gmail.com>
Merge "README: update to cm-10.2 branch" into cm-10.2
Merge remote-tracking branch 'cyanogen/cm-10.2' into cm-10.2