[youtube] SWF parser: Add opcode 86

Yes, I know we need 96, but an implementation of 86 could help avoid a similar issue.
[youtube] Add support for classes in swf parser
[youtube] Move swfinterp into its own file
[swfinterp] Start working on basic tests
[swfinterp] Extend tests and fix parsing
[swfinterp] Add support for multiple classes
[swfinterp] Add support for calls to instance methods
[swfinterp] Add support for calling methods on objects
[swfinterp] Correct array access
[swfinterp] Remove debugging code
[youtube] Correct signature testcase
Merge remote-tracking branch 'origin/master'