update sha.js

Okay this is the first change following https://github.com/dominictarr/crypto-browserify/issues/75

This will bring in recent updates to sha.js, adding support for sha224, and sha384

added algorithms are added features so the next version will be 3.5.0

Perhaps we could do this instead?

``` javascript
var hash = createHash(alg)
var blocksize = hash._blockSize

...

hash.update(key) // etc
```