Fix bug with non-zero anchor points

Also begin work on v1.1.2 in conjunction with particle editor

The particles were appearing at an offset from their desired location. This was caused by the anchor point being set to non-zero values. When the particles render, they call `transform.getConcatenatedMatrix()`. This incorporates anchor point data.

When the plugin was first written, KiwiJS had a bugged concatenated matrix system. Essentially it did not take anchor points into consideration and nested transforms didn't work right. Thus, when the particle plugin set anchor points (or, as they were then called, rotPoints), they were not taken into consideration and caused no problems.

After I fixed this bug, the particles all rendered properly - for the given anchor point, which was invariably off centre.

Setting anchor points to 0 restores desired functionality.
Fix bug where solo particle objects don't update uniforms

Per Github issue #9 the particles now set a `dirty` flag when config is updated. This forces an update to the uniforms, allowing lifetime properties to be edited or animated in real time.
Reformat README, tidy gruntfiles
Finalise readme