zshenv: localize variables instead of unsetting them.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
gitconfig: use shallow threading for patches.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
gitconfig: add several URL prefixes.

Private repositories on git.crustytoothpaste.net must be pushed to via SSH,
not HTTPS, so provide an appropriate prefix for that.  Also, provide a
prefix for other people's GitHub repositories.

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