Add Windows compatibility

On Windows you cannot run `py` files directly even if they have the proper shebang so call `pagekite.py` through Python to be compatible with Windows platforms too.
Allow an optional `frontend` option

Allows an optional `frontend` option to be passed and applied when not using an optfile.
Merge pull request #1 from BYK/patch-1

Add Windows compatibility
Merge pull request #2 from BYK/patch-2

Allow an optional `frontend` option
0.1.0