Added spark submodule
Merge branch 'master' of github.com:joshuaspence/dotfiles

* 'master' of github.com:joshuaspence/dotfiles:
  Cleaning up of some shell dotfiles
  Added some OS functions
  Added environment stuff
  Piped stderr to /dev/null to suppress errors in source function
  Added -readable test in source function
  Minor fixes
  Removed pager argument from ackrc as I don't believe that it is needed
  Removed superfluous whitespace
  Minor tidying
  Tidied up shell functions
  Tidied up shell aliases
  Removed Python-specific sublime-text-2 settings (I'm not sure what impact this will have)
  Minor changes to screenrc
  Added a github-pull-request script
  Added a git-rewrite-history script
  Added /etc/hosts submodule

Conflicts:
	.gitmodules