otatools: build-with-colors

- add new file for common functions and stuff
 - though it doesn't contain any function now ;)
- red color for errors
- yellow color for "Optimizing: *"
- cyan color for modversion :)
- green color for "package complete"
- and some general cleanup

Ported from jellybean branch

Signed-off-by: Michael Bestas <mikeioannina@gmail.com>

Change-Id: I83b2e352580e99b1766c5e63821281224cde5c49