Adding mouse support for SDL builds. Currently used for:
Look around:
* Left click to move cursor

Targeting:
* Left click to move cursor
* Scrollwheel to cycle targets
* Right click to fire
Use input_event struct to encapsulate mouse events
Fix 'if' block missing braces and const correctness
With circular distances on, make circular craters
Add a return statement to dummy getch_kyb_mouse definition in wincurses, in case that's causing some compilers to complain.
Fix food [a]ctivate
prevent inventory duplication on [a]ctivate, fixes clothing activation.
[a]ctivate lists all activatables.
Added more pack monster spawns.
Removed effect of sound on dynamic spawning.
Added Shia back to the game, gave him similar spawning to jabberwocky but rarer
Accidently spawned more jabberwocks instead of shias. Fixed.
Emergency vehicle overhead flasher lights! And a police car.
Aaaaaaaaaaaambulance!
Slightly lower the power of the flasher lights.
That's not how modulus works.
Future-proofing for circle lights that don't flash.
Proper initialization of overhead_lights_on.
Properly save/load overhead_lights_on state, without breaking old saves.
Emergency vehicles can spawn in cities now.
Merge pull request #3726 from ianestrachan/circular-craters

Craters circles instead of squares