[YouPornIE] Extract all encrypted links and remove doubles at the end
Add support for http://www.tube8.com
[YouPornIE] Make webpage download more robust
[Tube8IE] Escape dot in regex
Add support for http://www.pornhub.com
[Tube8IE] Fix regex for uploader extraction
Add support for http://www.spankwire.com
Add support for http://www.keezmovies.com
[KeezMoviesIE] Correct return value for embedded videos
Merge pull request #1661 by @rzhxeo

Add support for http://www.pornhub.com
Merge pull request #1664 by @rzhxeo

Add support for http://www.keezmovies.com
Merge pull request #1663 by @rzhxeo

Add support for http://www.spankwire.com
Merge pull request #1659 by @rzhxeo

Add support for http://www.tube8.com
Merge pull request #1657 by @rzhxeo

[YouPornIE] Extract all encrypted links and remove doubles at the end
Add the missing age_limit tags; added a devscript to do a superficial check for porn sites without the age_limit tag in the test