Add Windows support

[propheticbird]

I think we should be honest with ourselves and admit that there are some people who use Windows. It would be good to let them experience Holocron as well.

[ikalnytskyi]

Consider to use http://www.appveyor.com/ as CI on Windows

[insolor]

Actually, it works on Windows (I've tested holocron 0.2.0 on Windows 10, python 3.4.3), but it doesn't show the default post in the index of the blog generated with holocron init command:

However when I go to http://127.0.0.1:5000/2014/04/20/holocron/ directly, it shows contents of the post.

It works fine inside VM with Linux Mint 17.2 on board though:

[ikalnytskyi]

@insolor thanks for your feedback!

Holocron was designed to be OS-agnostic, but unfortunately I never had a chance to test it on Windows. I believe all problems aren't tricky to fix, I hope @propheticbird will find some time to fix it (I just don't have Windows machine to fix it myself :( ).