convert into a package that's installable as a console script

[lschumm]

i converted this library into a more standard-style python package. in order to do this, i:

• created a setup.py file that specifies package info, dependencies, as well as the fact that we want anaxi to be a executable from the command line
• deleted requirements.txt, since dependencies are already listed (with version tags) in setup.py
• moved package files into a folder called anaxitile so it can be bundled as a package
• instead of checking __name__ == "main", in tsdl.py, i've created a function called shell_invoke that is called when anaxi is called from the command line
• created an __init__.py that specifies what functions from the files in anaxitiles should be importable or runnable from the anaxitile package anywhere in python
• removed unused int() ;)