Interacter GUI/graphics library

Directory contents:
   * bin/ contains Windows (32- and 64-bit) and Linux (x86) static libraries (latter for older compilers only).
   * src/ contains a STUB library, with all subroutine and function
          interfaces, with empty bodies. This 'dummy' libraries allows
          one to build an application with all GUI-parts switched off
          by simply linking with libintstub.a (instead of libint.a).