Tested on single-monitor system and dual-monitor, where primary monitor does not start at (0,0) coordinate. Image transfer works fine.
Dual-monitor only has problems with receiving mouse cursor position and clicks, but this should be fixed outside of framebuffer plugin.
Compiles with gcc-4.9.4 and gcc-5.4.0.
Video of testing: https://www.youtube.com/watch?v=muGqjLWLrZA