Renamed BuildWarnings.cmake to SetupBuildWarnings.cmake.
Reworking CMake scripts.

- Following [this question](http://stackoverflow.com/a/23995391/2507444) I'll be switching to the target_<command> family of CMake commands.
- The new methods allow less bulky code for certain tasks, as such merging some functionality
  into main CMakeLists.txt now that it doesn't take up as much space, for ease of access.
- Working on learning how to use generator expressions. One issue I'm having right now is any
  whitespace in generator expressions is interpreted as marking a new list entry, which isn't
  working with how I want to format an or statement.