I've started to build Slider class

It's still incomplete, in fact, it's jus the beginning, but i had
nothing to do in a train.
Merge remote-tracking branch 'origin/master'

Conflicts:
	src/Menu/State_Menu.cpp
Revert "I've started to build Slider class"

This reverts commit f5a62171910419d7584e129dab8c270168371cca.
Revert "Revert "I've started to build Slider class""

This reverts commit 200b170434c29349ce7629bd38c8fe4830b0fe8b.
Upsssss

SORRY