Add ICU library to handle character encoding

[TheModMaker]

Currently, the only encoding that is supported is UTF-8 and UTF-16 (native). We should use ICU to handle the character encoding. The Codecs API can easily be used to abstract the encoding support. The big problem is that the ICU library doesn't have native CMake support. Plus the only Windows support is with Visual Studio, and doesn't support static builds. So we cannot easily create a standalone static build of ICU.

I started work with a patch that could be applied after checking out the code, but ran into problems with getting it to build correctly.