Remove rogue ';' in _git_info()
Fix tests for Windows by using File::Spec to get path to null device
Fix tests for Windows by using double quotes in CLI call (P:8/8)

In addition to *nix, now passes all tests on Windows 7 when running"

- Strawberry Perl 5.18.2 (via CMD)
- git 1.9.4 (via CMD, not Git Bash)