Can be further improved

[gorhill]

Good idea from @emn178 to pre-compute the value which is used twice in subsequent computations:

https://github.com/gorhill/yamd5.js/blob/master/yamd5.js#L152

Now I just wish he gave at least a polite mention that he did improve on others' work. I myself make clear I built on other's work.

In any case I will import the good performance improvement ideas (and properly credit), as I wish the library to keep the ability to compute hashes incrementally.

[lewisje]

Another potential improvement is writing part or all of this script to use asm.js, but even though your syntax is close, it still looks like a difficult thing to get right, considering how much you rely on strings.