Add salt state and master and minion states

Salt state includes both master and minion. Master state just installs
salt-master. Minion state installs salt-minion and sets the salt master
to be localhost.
Add latex state

This state is hard to categorize into one of the existing folders and
should probably be kept seperate anyway. The texlive-full package is
about two gigabytes in size; it could be useful to be able to easily
exclude this state rather than include it in a bundle like productivity.
Add users state and associated pillar example

State creates users with passwords based on a pillar. The actual pillar
I use is going to be kept in directory which is not committed.
Add doxygen to development state