Lots of minor changes (see full commit note).

- Change colour scheme.
- Remove left scrollbar in vertical splits.
- Tell Vim to look in .git folder for tags file.
- Install NeoSnippet, and base snippets.
- Install tComment.
Change airline theme to work with light colourscheme.
Add NeoSnippet settings.

These may still need to be tweaked.
Move Homebrew formulae list to brewfile.
Remove todo-txt.
Add .git_template to repo.
Remove trailing newline.
Remove Postgres / PostGIS hack.
Remove MAMP stuff.
Remove newline at end of file.
Add rbenv to brewfile.
Install global Ruby and gems.
Do not install ri or rdoc.
Merge branch 'develop'