Fix support for non English UI.

When git is localized, output is in the native language, so the regexp fails.

Forces output to be in English.
fix for issue #37 (branch detection with new git)
work around for vte.sh
bash-v4 or newer mandated
format consistently

- added sts=8 to modeline
- vim commands:
   :retab
   :%s/\s+$//
   gg=G
cleaned git-prompt.conf
retab on the rest of the files
Merge pull request #38 from killphi/cleanup

Cleanup
fixed: Makefile should have tabs
Revert "fixed: Makefile should have tabs"

This reverts commit bbac75bfa215cc07ad50db4670eebebeb5082ab4.
Revert "retab on the rest of the files"

This reverts commit 569178c05f02fa9f22a6fb7bd1baccf3765a866e.
Revert "cleaned git-prompt.conf"

This reverts commit 6ecb1d4b9d52f60d63694aac39ebeb0940193b9f.
Revert "format consistently"

This reverts commit 08f42056fd0e62ee53ab14b4fe95a2b5e04eed16.
Merge pull request #35 from maruel/fix_localized

Fix support for non English UI.
Allow configuration of the sed command to be used.

On OS/X, the builtin sed command does not handle the sed expressions
used throughout git-prompt.sh.  This commit allows customization of
the sed command to use in git-prompt.conf.  On OS/X, one could install
GNU sed instead (e.g., brew install gnu-sed) and modify sed_cmd to use
that.