Add release notes to the app for version 2.1.0
Merge pull request #74 from ocommowi/release-notes

Add release notes to the app for version 2.1.0
First steps towards rbZoom
-Solves the lost of control of focus over containers
-Improves rbzoom activation
-keyevent from qvtkwidget are sent to medMainWindow enabling the
activation of shortcut via keypressevent and keypressrelease
Small changes
removes useless lines