newbitmaps: Get rid of ImageMagick and use PIL for image processing.

To simplify dependency (and prepare for building inside chroot), we need to get
rid of dependency for ImageMagick, which is now entirely replaceable by Python
Image Library.

BRANCH=none
BUG=none
TEST=make # pass

Change-Id: Ie3d3a4ac399b2fe58aa75f8e02e4475bcba21c51
Reviewed-on: https://gerrit.chromium.org/gerrit/37985
Tested-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-by: Bill Richardson <wfrichar@chromium.org>
Commit-Ready: Hung-Te Lin <hungte@chromium.org>
6 files changed