Added back basic help info and welcome message
Added printing of default argument values. Hard-set help directory to /Users/workshop2014/revbayes (for Adelaide workshop computers).
Fixed problem with probability calculations for values outside of support in Bernoulli distribution.
Added categorical distribution (dnCat, dcat, rcat).
Better printing of strings (with quotes), default argument values, and option arguments.
Polished the argument mismatch message.
Modified argument matching so that type promotion occurs of constant assignable variables when used in a dynamic evaluation context.
Added help for categorical distribution.
Improved argument mismatch message
Added citation procedure and modified contributors procedure.
Changed version date. Registered citation() procedure.
Minor edit.
Merged with adelaide_workshop branch