Allow moving tests into IE files

Allow adding download tests right in the IE file.
This will cut down on merge conflicts and make it more likely that new IE authors will add tests right away.
Generate the list of IEs automatically

It seems like GenericIE needs to be last, but other than that, the order really does not matter anymore.
To cut down on merge conflicts, generate the list of IEs automatically.
Allow _TESTS attribute for IEs with multiple tests

This also improves the numbering of duplicate tests
Use str every time
[youtube] Fix tests in 2.x
Made generic IE handle more cases

Added a possible quote after file, so it can now handle cases like:
'file': 'http://www.a.com/b.mp4'
[soundcloud] Move tests
Made 'video' the default title for generic IE
[metacafe] move tests
[steam] move test
[eighttracks] move test
[youku] move tests
Remove superfluous name declarations
[infoq] move tests
[googleplus] move tests
Tests: Add coding to files
Merge pull request #954 from gitprojs/generic

Augmented Generic IE
Move tests to the IE definitions
Merge branch 'master' of github.com:rg3/youtube-dl
Credit @gitprojs for auengine