Fixed iOS compatibility.

This was entirely due to an erroneous set of quote marks in the default config object. `alpha: "1.0"` runs on most devices, but it is not technically correct. Changed to `alpha: 1.0`.

Fixed some other stuff along the way.

* Added jshint to grunt.
* Reordered large lists of config parameters, uniforms, and attributes to be alphabetical.
* Removed `_maxItems` property from `StatelessParticleRenderer` as it was unused.
* Removed duplicate uniform setting calls.