started port to glfw3
Implemented GLFW3 monitors. Separated GLFW2 code.
changed convention of v2 glfw imports to StdCall
Started implementing Window API of glfw3
Started implementing GLFW3 windows and input.
Added basic windows test. Fixed window API.
Made test work with both GLFW versions.

 * Introduced Display_Backend as GLFW-version-specific
   abstraction layer
 * To be able to implement it with GLFW 3, continued
   implementation of Glfw.Windows
Info about GLFW 2 / 3 in README
Finished window API.
Fixed GLFW tests. Added clipboard API & test.
Added missing functions. Updated my email.
+mouse cursor pos, +mouse test, +blending in GL