Fix realnumflames runtime error

- Declare realnumflames in create
- Make sure it and other calculated-in-draw variable updates aren't
  skipped if hosting
Make draw not affect state
Added contributing guidelines
Update contribution guidelines (less strict)
Added dropdownPlatform map entity
fix killcam on non 4:3 ratios
uh help
.gitignore
Finally fix this pain in the neck
cancel button take 2
Deduplication
satisfy ajf's pickiness
Don't prompt again for plugins when downloading a map
Simplified plugin prompts
Added comments for clarification; fixed ds_list_destroy() call
Elegance, and now it remembers plugins being skipped after 2nd map
Rename Contributing.txt to Contributing.md
Fix killcam closing 60fps