ADB Logcat colored output.

This patch adds a new '-C' option to logcat so that the output is
colored with colors similar to the ones in DDMS.
Simply type "adb logcat -C" to use it.
Works well with bash in gnome-terminal.

Change-Id: I8f6da4cf20e6d42094280672b0ab41a97b7ca797
Signed-off-by: Chirayu Desai <cdesai@cyanogenmod.org>