Windows compatibility

[chrisfls]

We must make preprocessor conditions to make Avalanche compatible with Windows.

[chrisfls]

I'm taking this issue and downloading MingW 32 bit now(64 only in the next milestone), "build on windows" will be fully tested soon.

[PedroHLC]

Everything is better by now, but we still search:
-GTK3 and Chipmunk for Mingw
-Vala 0.20.1 compiled for windows.
[do not reply]

[chrisfls]

Gtk3 for Mingw can be found in openSUSE repos right now, we just need an automated way to keep our versions up-to-date, this could be done using an custom package manager (like my mingman), but man, it is way time consuming to make an package manager (even if using ruby), mingman source can be found here:https://github.com/kress95/mingman.

I think that porting avalanche to windows might not get /really/ that hard, but porting valac to windows will be a mess.

[PedroHLC]

People can now find Windows ports of librarys and Vala in "Useful files" wiki page:
https://github.com/avalanche-games/avalanche/wiki/Useful-files

[chrisfls]

To close this issue we just need to get the editor working on Wine/dows.