Add modal window for medium and small screens.
Add sticky footer.
Fix flash of unstyled content.
Add sticky footer.
Add drag and drop.
Fix flash of unstyled content.
Fix drag and drop bug in IE.
Merge branch 'master' of https://git.itechart-group.com/scm/git/linguasys.dev

Conflicts:
	CorsTestClient/CorsTestClient/UI/Scripts/draganddrop.js