Switch from Agnoster to 9k
Switch from Agnoster to 9k

This patch needs an additional step to work, but its not worth dealing with
nested git submodules right now.

```
$ git clone https://github.com/bhilburn/powerlevel9k.git
~/.oh-my-zsh/custom/themes/powerlevel9k
```

1. Supports shortening of long paths, Go makes this so necessary.
2. Neat support for prompts on the right side, even though I might not use it.
3. The comfort of being able to retain the old color scheme!

Wishlist:

1. Change vcs color prompt for untracked files as well.

jaseemabid/dotfiles,jaseemabid/dotfiles,jaseemabid/dotfiles,jaseemabid/dotfiles,jaseemabid/dotfiles