Tiny cleanup for button rendering.
Remove unused SWEEP and ERRATIC-DIRECT weapon movement types. Cleanup weapon loading.
Misc cleanup
qtscript: Change eventResearched() to always have 3 parameters, where the
new third parameter is player called. Second parameter may be null.

Remove unused power parameter for ECM. Remove some dead code.
Eliminate bison/flex dependencies from the mac builds.

References work done in 372eff669.

Refs #3887, #3538, #3950.