Fix confusing include paths

[ebchin]

Projects that use the tribol, redecomp, and tribol_shared libraries have include paths that don't make it clear that the source of the include is Tribol. See, for instance, this comment.

Perhaps we could move all the installed header files to the path include/tribol/[tribol, shared, redecomp]? Thoughts @white238, @srwopschall, @chapman39?

[chapman39]

that could work, sounds good to me.

alternatively, and maybe this wouldn't make sense but - what about moving redecomp and shared into src/tribol?