Added _trial_temp to .gitignore
Moved bitcoin.py tests to their own file

This allows standard python testing tools to discover and run them.
Added private/public key tests

Including converting from a private key to a public key, and
deriving the primary address from a private key.
Made _do_test_crypto private to allow nosetests
Added travis config file.
Made travis only run on lib/
Merge pull request #731 from chrisglass/refactor-tests

Refactored tests, wrote tests, added CI config file.