gitconfig: turn on precomposing Unicode.

Not that I do a lot of development on Mac OS X, but it's just safer to have
this on for all repos.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
ct_grey: mark as MIT licensed.

Todd Werth has confirmed that his ir_black theme is licensed under the MIT
License.  Add a credit and comment to that effect to ct_grey.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>