convertToGrey method works, it needs tweaking in the values used for the
conversion.
method convetToGrey alone, nothing else is changed
Merge branch 'debugNesvi' of https://github.com/Nesvi/PhotoVision.git
into debugchaussi

Conflicts:
	src/es/ull/etsii/VPC/Controller.java
	src/es/ull/etsii/VPC/FotoReVision.java
Added Actions class for implement the operations over the image and the
way to use them from the gui.