Main novelty:

- Added the sub-module "Dynamics" within the "Visualization" module, allowing to visualize/export snapshots of a given dynamics on the top of a multiplex network. Possibility to make an animated movie through ffmpeg included.

Other:

- Solved some issues with file paths when running on Windows
- Minor bugs in the GUI solved
- Added possibility to keep desired orientation in successive renderings (it's useful!)
Merge commit '4ba6ad1d0161e6d2f404134aabba26ec1d76b323'

Conflicts:
	export/empty
	muxVizGUI.R
	tmp/empty