Revert "taken out mlscripting (for now let's pause the development of this)"

This reverts commit 5caee5bc871925f2b94bed3fc4e0b9b075774e0f.
Adapted codebase to Qt 5 and clang compatibility (mac)
Fixed problem with HiDPI (Retina) displays in which OpenGL 3D samples were being drawn at half size
ADDED: LLE, Metric Learning, Random Kernels (from students)
restructuring of the plugin management system (cleaning up mldemos class)
Merging the requests
Merging requests
Merge branch 'devel' into debian-devel