Add initial Lua scripting structure

Add some more (basic) XF functions

Fix I_Error not printing out errors before console would be initialized
Roll X_LoadScripts into X_Init
Merge branch 'master' into console
Start moving overlay code into scripting
Pull more HUD functionality into scripting
Don't segfault if IWAD is missing (must've been due to a bad transcription)
Disable signal handling in debug mode
Ignore Code::Blocks Debug folder
Merge branch 'console' into scripting