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
Provide ability to revert back to the previous version of powerline
Add <leader>gw for :Gwrite in fugitive
Added the branch via bash variable to the git pull command when updating.
Merge pull request #353 from rraub/3.0

Added the branch via bash variable to the git pull command when updating...
Merge pull request #352 from johntyree/Gwrite

Add <leader>gw for :Gwrite in fugitive
Merge pull request #345 from mmikitka/toggle_powerline_version

Provide ability to revert back to the previous version of powerline
Update GitGutter after writing to the index.
Add GitGutter toggle similar to other git shortcuts.

All of the other shortcuts are related to fugitive, but I feel that it's best to
just put the "git-related" shortcuts together. <leader>gg shouldn't conflict
with any git commands other than grep, which probably much less frequently used.
Merge pull request #356 from johntyree/GitGutter

Update GitGutter after Gwrite
fix ctrlp working_path_mode
Use elzr/vim-json instead leshill/vim-json

leshill/vim-json will NOT be updated anymore, again.
Merge pull request #365 from JoveYu/3.0

fix ctrlp working_path_mode
Merge pull request #367 from perfectworks/3.0

Use elzr/vim-json instead leshill/vim-json
skip neocomplcache configure if use snipmate
Merge pull request #376 from perfectworks/3.0

skip neocomplcache configure if use snipmate