[tests] Don't auto init YoutubeDL

It would print the debug headers for each test.
And nose uses a StringIO object for stdout, which in python 2.x doesn't have the 'encoding' attribute.
Do not override stdlib html parser 'locatestarttagend' regex (fixes #4081)

'<a href="foo" ><img src="bar" / ></a>' wouldn't be parsed right (the problem is '/ >', '/>' worked fine).
We need to change it in python 2.6 (for example the description of youtube videos wouldn't be extracted).
[trutube] Strip title
[test_compat] Ignore unicode_literals
[brightcove] Make _VALID_URL less greedy and check for empty URLs (#3541)
[generic/brightcove] Add a new test case for kijk.nl (#3541)
[wimp] Fix video URL regex
[played] Capture and output error message
[cnn] Modernize test definitions
[youtube] Skip sts if missing (Fixes #4095, fixes #4103)
[gamespot] Modernize