Initial refactor of tests
Refactor tests [https://github.com/izaera/cipher/issues/1]

Refactor tests to create generic tests based on BlockCipher, StreamCipher, Digest, etc. interfaces.
Define an API similar to JCA to be able to create/extend algorithms by name (fixes #13)

For instance: var c = new BlockCipher("AES/CBC");
Prepare benchmark framework and integrate it with command line tool (fixes #11)
Initialize ciphers in a generic way when benchmarking (fixes #17)
Allow block algorithm chaining (fixes #14)
Updated readme
New tool for creating dartdocs
Prepare for version 0.3.0
Refactor libraries names for documentation

Also changed visibility of a method and added license headers to all files