edx/edx-platform — pull request #3883 by polesye (2014-05-27 10:34:54+00:00)
Title: Fix youtube regular expression in video player editor

Ticket: [BLD-967](https://edx-wiki.atlassian.net/browse/BLD-967)

In this PR, regexp is changed, updated unit tests, fixed docstrings.

@auraz please review.