Added static RNGseed control

 - rngseed CCMD. Using the get allows you to view the current rngseed, set <value> allows you to set a static rngseed for the next game, and clear unsets the static rngseed.
 - "-rngseed <value>" command line arg sets a static rngseed. This allows for netgames or recordings to also use the set rngseed.