Added two new statements: prepush and postpop. These are code blocks that are

Added two new statements: prepush and postpop. These are code blocks that are
written out during call and return statements immediately before pushing the
current state to the state stack on a call and immediately after popping the
current state on a return. These can be used to implement a dynamically
resizable stack. Test cases are in test/recdescent?.rl.

git-svn-id: http://svn.complang.org/ragel/trunk@280 052ea7fc-9027-0410-9066-f65837a77df0