Added new example showing offscreen rendering (GPGPU example here) without any visible window.
Implemented __getitem__ and __setitem__ in ColorArray.
ColorArray.__getitem__ now returns a new ColorArray instance.
Text has point_size and pos properties

And text always draws in that point size, even if inside a viewbox.
Text: can set color, and supply pos and point_size in init
Added assert raise statements in ColorArray tests for __getitem__ and __setitem__.
ModularShader: Fix that program is not recompiled on prepare()

... unless necessary
Address comments
Updated README.
Fixed dash character.
Text: address comments
flake
Added notes about the subpackages.
Added some backends.
Text.pos does not use transform.
Text usable in normal canvas
Merge pull request #404 from rossant/colorarray-indexing

Implement __getitem__ and __setitem__ in ColorArray
WIP: EGL backend
FIX: Add to Travis
FIX: Minor fixes