-Doc: Fix Doxygen errors.


git-svn-id: https://freerct.googlecode.com/svn/trunk@1355 d3bf82d2-0c16-e458-5408-27be57bd1276
-Codechange: Refactor obtaining viable exit directions from the current tile to a new function (sgtbigman).
-Add: Initial Employee code.
-Codechange (minor): GetInparkDirections now returns only valid in-park exits.
Merge branch 'add-employee' of https://github.com/sgtbigman/FreeRCT into add-employee