GitLab

Changes method git_parse_ahead() on git.zsh lib file. Before this
change it checked directly against origin/master branch. Now it
uses $(current_branch) to check for not pushed changes against
the current remote branch.

Modifies the Git lib file (lib/git.zsh), adding three new prompt
methods:

- git_prompt_ahead(): Shows the content of the custom var
  $ZSH_THEME_GIT_PROMPT_AHEAD if the local repository has
  commits ahead from the remote origin repository

- git_prompt_short_sha(): Shows last commit SHA hash in short
  mode wrapped between the content of the custom vars
  $ZSH_THEME_GIT_PROMPT_SHA_BEFORE and
  $ZSH_THEME_GIT_PROMPT_SHA_AFTER

- git_prompt_long_sha(): Shows last commit SHA hash in long
  mode wrapped between the content of the custom vars
  $ZSH_THEME_GIT_PROMPT_SHA_BEFORE and
  $ZSH_THEME_GIT_PROMPT_SHA_AFTER

Initial implementation of a new plugin system, so that people can managed which aliases/functions they want.

(via git status -s, benchmarked)

Moving all zsh config options into a lib/ subdirectory to make way for some upcoming changes to directory structure and configuration options

`git-symbolic-ref` needs to be `git symbolic-ref`

 * Improved speed, the first time cd'ing into a git repo the prompt
   returns much faster (for me at least).
 * Prompt is now decorated in nested folders within a git repo. No
   longer check for the '.git' folder.

 * git.zsh is now themable:
   * git_prompt_info() now will look in the following variables for
     formatting strings:
     * ZSH_THEME_GIT_PROMPT_PREFIX - Prefix for the prompt (before the
       branch name)
     * ZSH_THEME_GIT_PROMPT_SUFFIX - The very end of the prompt
     * ZSH_THEME_GIT_PROMPT_DIRTY - Displayed when the branch is dirty
     * ZSH_THEME_GIT_PROMPT_CLEAN - Displayed when the branch is clean
 * Updated geoffgarside, robbyrussell, and maran to work with new git
   theme
 * Added the Risto theme, which is very similar to a number of bash
   prompts, and allows me to use zsh in with out my co-workers knowing I
   have the advantage. Think of it as a ninja theme.