crypto: use packages directly

[dcousens]

This reduces the browserify build size from 600k to ~300k. While most apps may include crypto anyway, they all fall back to the same modules as this is what crypto uses in browserify.

Not indifferent to using require('inherits') vs require('events').inherit

[coveralls]

Coverage remained the same at 99.16% when pulling 64e206c on buildreduce into 03f3ccf on master.

[dcousens]

Will merge after TRAVIS passes

[coveralls]

Coverage remained the same at 99.16% when pulling b558747 on buildreduce into 03f3ccf on master.

[rubensayshi]

awesome!