Merge pull request #324 from reakinator/event_default_constructors

added default constructors to KeyEvent, TouchEvent, and Touch
Added modifiable accessor for touches on TouchEvent
Screensaver docs
Merge pull request #323 from reakinator/texturefont_glyphplacements

Texturefont glyphplacements
Initial upgrade to AntTweakBar 1.16
Retina support for params::InterfaceGl
Moved AntTweakBar source to Other Sources in XCode project
Multi-window support for AntTweakBar
MSW AntTweakBar fixes
added smaller size capture for AVFoundation implementation
uncomment code that fixes capture orientation on iOS - in the long run this needs to be set by a public parameter