Some changes to be compilable in mingw

[racerxdl]

I made some changes to be compilable in mingw32. Also I changed README to be in markdown and put instructions to generate a linkable library in MSVC.

Also tested on Linux, its working fine. It worth try to test in MacOSX as well to see if anything is broken.

[brian-armstrong]

Hi Lucas,

Thanks for the patch. I'll take a look at it later today and will look at applying it.

But since you're here, have you considered using my libfec replacement, libcorrect? It builds under CMake though I haven't tested it in mingw. libfec's author does not seem to be actively maintaining it, but I'm still working on libcorrect. And libcorrect can be built as a compatible "libfec" file by building its shim, so it's fully compatible. I'm already using it instead of libfec in my Android port of Quiet. /shamelessplug :)

[racerxdl]

Sure! I didn't know about libcorrect. I will take a look on it. I mainly use this libraries in Linux Platform (my GOES Satellite Decoder http://www.teske.net.br/lucas/satellite-projects/ ) I will take a look and I may port my app to use libcorrect ^^