Fixes for VS2015 and CMake 3.0

[cdglove]

• Use full paths to include files and pch files.
• Link to output lib for MSVC 2015
• Add missing CMake 3.0.2+ flags.

There might be a better way of doing this (I'm not a cmake guru), but this changes for things working for me.

[cdglove]

Had to have the lang as CXX for VS for some reason or the file would not be built.

[m4c0]

Doesn't it means we need to change cmake_minimum_required to 3.0.x?

[onqtam]

@m4c0 cmake 3.0 is already old so it shouldn't be a problem

[onqtam]

I cannot stress enough how important sharing precompiled headers between targets is to me... (500 plugins as .dlls)

Is this project even alive? Add a donate button and I will donate...

[nanoant]

It is not really dead, but neither fully alive ;) I have new job and right now I am kind of overwhelmed by my new duties, however I will have a look at these PRs this weekend and see what I can do.
Moreover my solution (this project) is kind of workaround. Proper solution would be to somehow make CMake itself to be aware of precompiled headers, rather use the tricks. This was somehow proposed to KitWare, but never made through.