Remove deprectated Heroku gem, add CLI client

The Heroku gem has been deprecated, and Heroku recommends installing the client CLI from toolbelt.heroku.com. It's a binary, but you can install the "standalone" version (https://toolbelt.heroku.com/standalone) via wget.
Change wget to curl in Heroku CLI setup script

wget isn't pre-installed on OSX machines.
Merge pull request #45 from kevinSuttle/patch-1

Remove deprecated Heroku gem in favor of CLI client
Install ctags for tab completion in vim
Use absolute path to Heroku since the Toolbelt isn't in $PATH yet
Source rvm function after install

* Follow RVM loading instructions from https://rvm.io/rvm/install.
* Unlock from RVM version 1.15.10, which was being used because a later
  version was broken with zsh, which has since been fixed.
Create Postgres database after install

This follows the current instructions printed by Homebrew.
Install Redis

It is common enough on the thoughtbot client projects I've seen this
year to want to install it on machines by default.
Install watch
* example: watch heroku ps --remote production
Update the logo to point to the assets path.
Update copyright year range through 2013
Remove unnecessary bit in install instructions
Restart shell after mac script finishes

* Assure installed items and env vars apply.
* Fixes https://github.com/thoughtbot/laptop/issues/63.
Manage Heroku CLI with Homebrew

https://github.com/thoughtbot/laptop/pull/67
Mkdir /usr/local for Homebrew if it doesn't exist
Merge pull request #69 from thoughtbot/ctoomey-mkdir-homebrew

Mkdir /usr/local for Homebrew if it doesn't exist
Use rbenv to change Ruby versions

* Use Homebrew consistently for OS programs.
* Use ruby-build to install Rubies.
* Include auto-switching of Ruby in `~/.zlogin`.
* Upgrade Rubygems after Ruby is installed. This is to help avoid common
  Bundler/Psych issues:
  https://github.com/tenderlove/psych/issues/66
* Use newest Bundler version in order to work with latest Rubygems.
* Use rbenv-gem-rehash so the shell automatically picks up binaries
  after installing gems with binaries.
Add new libraries to README
Alphabetize libraries in README
Force gcc-4.2 compiler when installing Ruby

Avoid errors like:

    st.c:520:35: error: implicit conversion loses integer precision:
    'st_index_t' (aka 'unsigned long') to 'int' [-Werror,-Wshorten-64-to-32]
    i = table->num_entries++; ~ ~~~~~~~~~~~~~~~~~~^~

https://github.com/sstephenson/ruby-build/issues/287