v2 release candidate 14

• .toString() now supports subKernels, and pretty much every feature we can think to throw at it
• Proper fallback support for HTMLImageArrays in WebGL
• Upgrade to latest HeadlessGL
• Start of implementing bitwise operators, though very low precision
• Implement new float encoder when using unsigned precision
• Breakup of argument and constant handlers into unified class called KernelValue
• RawOutput feature
• Pixel flipping for kernel.getPixels()
• Dynamic recompiling
• Breakup of texture handlers into separate classes, so no duck typing
• Handle textures in CPUKernal
• Allow for canvas resizing

Housecleaning for v2.