Add fugitive navigation enhancements

The tree buffer makes it easy to drill down through the directories of
your git repository, but it’s not obvious how you could go up a level to
the parent directory. This new mappings ".." helps.
Add numbers.vim to vundles.list

numbers.vim is a plugin that allows for easy switch between
absolute and relative line numbers.
A convenient shortcut: ,tn (toggle numbers) is provided to
switch between the two modes

Fixes #276
Update plugin mgmt help on README.md

We now have a working yadr vim-delete-plugin
Updated pry readme to reference jazz_hands gem
Disable automatic switch of line numbers

Fixes #296
Revert numbers.vim causing relative numbering issue
Externalizing and improving search configuration
Merge pull request #301 from lfilho/insensitive-search

Externalizing and improving search configuration
Fix: [Zsh] load ssh-agent module
Merge pull request #304 from petRUShka/load-ssh-agent

Fix: [Zsh] load ssh-agent module