add collecting and delivery of statistics
fixed KeyError, added try/except block
found another KeyError, fixed
added collecting and delivery of statistics of sections of courses
a little improvement
bug fix
about display fix
about editor fix
social fix
Merge pull request #53 from pelikanchik/alexg

Alexg
fixed bug with math tags
Merge pull request #55 from pelikanchik/timur

Timur
Merge pull request #56 from pelikanchik/master

update from master