Update tests to run correctly on testling.

We can't run node's version of crypto on testling, so tests were
actually comparing the test code of crypto-browserify with whatever
version browserify happens to pull in (0.2.x iirc).

Tests are now split into two similar files, one runs in node to
keep the comparisons against node's crypto updated, and the other
compares crypto-browserify's output to a cached copy.
Add missing reference to Buffer class
Merge pull request #17 from legastero/master

Update tests to run correctly on testling.