moving/merging some files over to the sdk dir; compiling under macosx as a dylib, but that's about it for now.
removing kernel files from sdk; this is application logic
prism is now linked with libgemini
update library with gemini namespaces for consistency
Fix build script for gemini; removed redundant src/sdk path.
Fix namespace resolution to gemini::memory
removing files from old location; fixing up references to use sdk
remove hard-coded references to files in build script
removed gemini namespace from sdk files; adding filesystem

I've removed the gemini namespace from the sdk. It's a bit annoying to convert
everything (including the app) over at this point. I can do it all later,
if I choose.

The filesystem is starting to get fleshed out and has been moved from gemini
over to the library.
converting code to use libgemini
moved xfile to libgemini; fix stackstring references to xstr
fix shader version commented out; fixed comment in gemgl; restored other functions

This is a first pass to fix #16.