Rebased fixes for canvas masking/renderMode

Massive documentation update; fixes many issues. ...

Issues fixed by these documentation updates:

- #1973, fixed filter and BitmapText property docs
- #1908, fixed type reference links
- #1856, fixed name of MeshShader

fixed canvas renderer options bug; added roundPixels to default render options

add missing drawCount increments

CavasRendered.roundPixels can now be set from options

missed a semicolon..

fixes #1850 ...

bit of a funny one.. when at the canvas is resized we now set the scale
mode again as it seems to be reset

uuid is a misnomer, this is not universal, but it is unique in the scope of pixi ...

Added deprecation for uuid

add bool uniform support in the shader

Expose drawModes like blendModes ...

This separates the pixi contant value from the GL constant value. Even
though right now they *should* be the same, if there are platform
differences, or changes in the future ours will always work this way.

properly initialize projectionMatrix; fixes #1811

fix #1790; add exports that got removed in 928477c

minor jshint fixes

properly handle context restore; fixes #1788

doc tweaks

more doc clean ups..

fixed extends doc issue

stub destroy method for canvas mask manager, fixes #1744

fix webgl manager destroy to remove correct event handler

5x5 to 5x4, fixed some wording and general cleanup

remove some private docs

fixed initial filter texture upload bug

fix #1727 move viewport resize

resize gl viewport in webgl; fixes #1712

update for new event emitter api

reset drawCount each render call; fixes #1661

fixed a bug i introduced ...

because I’m a donut..

Fixed filter area clone bug

fixed filter issue

fixed filterArea bug