Link to directory of bootstrap

If we're already in a git directory, we should link the files here.

Use case: I add spf13-vim as a submodule of my dotfiles.
Set endpath properly

Set endpath to the location it's being called from so we can
check if we're in a git directory or not
replace to new powerline
Merge pull request #339 from Gohan/fix_powerline

replace to new powerline
Merge pull request #328 from joshbetz/patch-1

Link to directory of bootstrap
pulled from upstream