bug fixes, added ability to specify output directory.
bug fixes, added ability to specify output directory.

* added ability to specify an output directory.
* added missing quality profiles.
* handled exception when unexcepted quality profile returned.
* videos now get sorted by quality profile.

garg10may/pytube,pytube/pytube,mserjx/pytube,garg10may/pytube,DomainGroupOSS/pytube,harsham05/pytube,DomainGroupOSS/pytube,mserjx/pytube,harsham05/pytube