Don't cache CtrlP results when using ag

It gets very annoying to manually force CtrlP to re-index every time I
add a new file. Since ag is so fast, we can turn off caching when it
powers CtrlP without any noticeable impact on search speed.
Allow backspacing over everything in insert mode

The previous setting frequently slowed my ability to edit.
Set 'autowrite'

* Automatically :write before commands such as `:next` or `:!`
* Saves keystrokes by eliminating writes before running tests, etc
* See `:help 'autowrite'` for more information
Add envup script for loading environment variables
Globally ignore `.env` file

It is a common practice to store environment variables in a .env file in
development. This file is read by tools such as foreman and dotenv. This
file can contain sensitive information such as secret keys and should
always be excluded from version control
Updates dotfiles to have .local files as needed

* in favor of the old way of #DO NOT EDIT BELOW THIS LINE, dot files
* were changed to have local config files - updates local dotfiles ot
* match this preferred pattern
Adds git plugin back for git branch auto completions
updates source path
Color and alias tweaks
Adds rspec mappings