UI: add Omega.Gen.random_loc js generator
UI: implement Location#add, + couple fixes/improvement to loc

Updates direction_to to properly reflect direction from location
to target & usage in canvas.js

Also small addition to canvas defining common callback method
to reanimate canvas, for use in other components
UI: add flags to toggle ship highlight & hp bar gfx

Also handles a few trail edge cases for ships w/out
configured trails
UI: add trail to transport ship
UI: add new 'tech demo' cutscene