removed obsolete tokenizer
Merge remote-tracking branch 'github/exch' into dev

Conflicts:
	src/Nubuck/common/common.cpp
basic signed distance font rendering
added alphatest to state
use alphatest for sdfont

replace shader discard with fixed function alphatest
fixed uninitialized memory bug
added background gradient
removed 'Choose Background Color' menu item
renamed bgColor to clearColor
uncheck checkbuttons when operator is invoked
fixed depth peeling bug
workaround for orthographic projection bug
refactored R::Material
switching to desktop