zsh: remove old color scheme.

The old bmcdark colorscheme never really worked, and it would be better to
simply refactor the existing bmc scheme to use different colors if necessary
anyway.

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

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Xsession: use MATE if available.

If MATE is available, use it; otherwise, use XFCE.  Run this under zsh so
that the proper environment variables are set.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Merge branch 'master' into work