Implements developer mode command to reload Rules and Art files.

[CCHyper]

This pull request implements a new developer mode command, allowing you to reload the Rules and Art files while the game is running.

It will reload the files in the following order; ART.INI (ARTFS.INI) -> RULES.INI (FIRESTRM.INI) -> Scenario overrides.

Warning: This could very well crash the game, please use it with caution, and make small incremental changes only!