Large patch on engine components

- Removed engine, made select components part of new engine library
  module
	- Removed common.h/.c, no longer needed
	- Moved GL wrapper functions to glwrap.h/.inl
		- .inl file is to be included in a single source file for
		  an executable build, to define the wrappers declared in
		  the header file.
	- Add application struct
		- Has an API for various tasks that might be shared across
		  different types of applications.
	- Add new config objects
		- Read config files which consist of lines containing
		  a field and value in the format:
		      Field1 "Value1"
		      Field2 "Value2"
		- Need to test writing/saving configs as well as do memory
		  checking.
	- Add window.h/.c with window config code. Since the new config
	  object could serve this purpose, everything except the
	  window_config struct may be removed.
		- Incomplete API functions
- Added client and server executable builds
	- Need to tweak build a bit so that server-only or
	  server-and-client builds can be done as desired. Server-only
	  builds won't need certain libraries like GLEW or GLFW, but
	  the server-and-client builds will need everything.
- New error codes
	- FILEOPENREAD
	- FILEOPENWRITE
	- FILEOPENAPPEND
	- FILEREAD
	- FILEWRITE
	- CONFIGFIELD
	- CONFIGVALUE
	- CONFIGSETTING
- New core header, util.h
	- Contains helpful functions, e.g. bitfield controls