Added simple version of new tokenizer -- completely untested.
Cleaned up Actions and Enums.

Simplified the action definition/constructor and added a docstring to
enum constructor.
Because of the line->block transition in the language, action objects
can't be built out of lines. Instead, an action will take a command
list as a direct argument to its constructor.
Cleanup of tokenize.py and removal of obsolete modules.

Removed the line and manifest modules, switched the sample manifest
to the new manifest format.
Added comments throughout, better encapsulated functionality in
tokenize_stream(), fixed several typos in the state machine, and
made the enums more uniform.

Added nosetest support to the lib package.
In order to be scanned by nosetests, packages need to be identified as
such by an __init__.py file. Here we add these to the lib package and
subpackages.
Added tests for Enum and tokenizer, fixed tokenization bugs.

The Enum tests verify that the behavior of Enum objects remains as
expected. This mostly protects against future, unplanned changes that
may break extensions of python-SALVE which use Enums.
The addition of tokenizer tests revealed several bugs, which have now
been repaired.
Merge branch 'feature/basic-tokenizer'