Slightly faster version of resize2.js available

[mn4367]

Rescaling with bilinear, bicubic, bezier and hermite interpolation is a bit slow. I'm using a copy of resize2.js in my own icon generator and refactored it. I inlined all functions which sometimes got called for every single pixel. This speeds up rescaling a bit. Feel free to use this version resize3.js which is otherwise identical to the original resize2.js (apart from the removal of the options parameter which was never used).

There is also resize4.js with an alternative bicubic implementation that is much faster. The limitation of this version is that source and target image must have the same width/height ratio.

[hipstersmoothie]

@mn4367 PRs welcome! This is a community project and any help is appreciated