Merge pull request #34 from pelikanchik/bt

Bt
Merge pull request #35 from pelikanchik/bt

Disabling of buttons while sending answers to the server; fixing bugs co...
Merge pull request #36 from pelikanchik/bt

Bt
Merge pull request #37 from pelikanchik/bt

Bt
tags
Merge branch 'alexg' of https://github.com/pelikanchik/edx-platform into alexg
buttons z-index fix
buttons z-index fix
tags fix
tags fix
graph alert fix
dynatree fix
dynatree fix
graph fixes