Title screen cheat "devmode".

Access the benefits of -debug, console devmode, and a complete gamedata.dat (all secrets unlocked) all in one go.
Moved "#if 0" and "#if 1" to "#ifdef DEVMODE" so the existance of this cheat and MD5 validation and all that can be toggled in one place too.

git-svn-id: https://code.orospakr.ca/svn/srb2/trunk@8998 6de4a73c-47e2-0310-b8c1-93d6ecd3f8cd