Move VERSION string to its own file

[Crazybus]

Pip installs for lambkin are currently failing because the setup.py tries to import all dependencies when trying to import the VERSION string.

pip install lambkin                                                                                                                                                                                                                                                                                                                                  
Collecting lambkin
  Using cached lambkin-0.3.3.tar.gz
    Complete output from command python setup.py egg_info:
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/private/var/folders/72/fg_n7npd4pj4pdvzxrj7qmt40000gn/T/pip-build-bhSObD/lambkin/setup.py", line 4, in <module>
        from lambkin.lambkin import VERSION
      File "lambkin/lambkin.py", line 4, in <module>
        import boto3
    ImportError: No module named boto3

This change moves it into its own file so that no extra dependencies are required to get the version.

[jarpy]

Thanks for helping to keep this old chunk-o-mutton ticking along.

[jarpy]

Published to PyPI.

https://pypi.python.org/pypi/lambkin/0.3.4

[Crazybus]

Thanks @jarpy pip install lambkin works perfectly now!