Security fix: faked urls

Backend detection hasn't been resistant against faked urls like:

http://youtube.com.myurl.com/watch?v=abcde
http://vimeo.com.myurl.com/watch?v=abcde

It is fixed and added few tests to cover it.
Closes #5.

Add {{ my_video.backend }} containing YoutubeBackend, VimeoBackend or SoundCloudBackend values.

- Fix: SoundClound --> SoundCloud
- added tests for template tags
I haven't found any situation in which can be UnknownIdException raised, so I removed this lines. If anyone find such situation, please return it back and write appropriate test case.
Release 0.3
Add Django 1.5.2 to Travis
Sites using django-embed-video in README
Merge commit '0fdc6a3df75813235a4d6beafc250dcb3d3cfabd'
Rename embed_video.base to embed_video.backends
Sphinx doc
Documentation link and Quick start
Remove SSL from link to docs
Ready for Python 3
Old version of Django doesnt support Py3
Remove Py2.6 from Travis
new regexes

- updated detection for youtube to detect ok without protocol
- updated detection for vimeo to detect ok without protocol
- updated vimeo video ID finding regex to handle embed video url format 'player.vimeo.com/video/ID'
- updated youtube url to match more of the multiple youtube url formats
Fix: coverage reporting
--source option is redundant with .coveragerc
--source is redundant
Merge commit 'ef614d8bf038c4518b6869993e24981b81e67c36'
Merge commit '1040bb1a60b796885de5860e254d210fbacbed18'