Vega Strike Code

Merge previous particle improvements from trunk of which the last commit was dependant on

nevermind about isSun, but getRadius is still good to have since before only Unit could access Planet radius

Minor fixes to particle (reduce logging verbosity, fix out-of-sync comment)

Merge particle system fixes and optimizations from trunk

some minor cleanups and fixes

Issue #3608250: Make intro text show when you click on a new campaign,
for mood setting, and try to be more robust when looking for the intro
text file (create absolute paths based on path to module)

Make max particle limit adjust to GPU capabilities automatically.
Optimize particle deletion.

This is an attempt to reset fairness in scheduling in the game. Basically, since we're not threaded we have to decide how many physics updates we want to run per draw and this more closely tunes things to the settings the player makes with Computer (simulation_atom size). It's important when testing this commit to see if it should be reverted to make sure your settings are matched to your computer. Slow framerate will == jerkier behavior, but game speed should remain divorced from framerate for the most part

-O options are now their own flag and independent of Build Mode or CPU opts. You can mix and match all 3 settings. We still need to do a better job at ensuring flags work with the current gcc version in use, however.

removing a Unit pointer from a collection should only need to traverse until the first unit match, we dont put multiple copies in a single list. Also some minor const optimizations and unit_collide was re-creating a function already in collection