vimrc: add checking for spaces before tabs.

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

This is needed because some programs don't pass the values of EDITOR and
VISUAL through the shell or expand spaces, leading to attempts to invoke a
program called "gvim -f" containing a literal space.  Since obviously this
does not work, using this program provides a workaround.

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