gitconfig: switch to histogram diff.

This produces better results than either patience diff or the myers
algorithm when moving large chunks of code around.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
vimrc: retain old whitespace stripper as <Leader>zw.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Xsession: enable Ctrl-Alt-Backspace.

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

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