SJCL

This PR migrates Crypton from CryptoJS to SJCL.

There are some inherent changes in this, notably a looser schema to accomodate SJCL's serialization techniques. This also includes a fix for #25 with a revamped challenge protocol using bcrypt. There are also smaller cleanup changes.

Tests are where they were when I created this branch, with the exception of a clarified postgres driver test (changed to reflect the new columns). To run the tests,

    cd crypton
    make

To test the examples, in one terminal do

    cd crypton/server
    npm link
    cd ../integration_tests
    make clean-test-db
    make setup-test-environment
    NODE_ENV=test crypton

and in another do

    cd crypton/client
    sudo http-server -p 80 .

and navigate to localhost