Get available qualities instead of bitrates

A quality is a bitrate + a resolution.

This patch does not change the user interface. qtoutv is still
using its absolute list of resolutions.
cli: print resolution only if available
qtoutv: Better logging format
qtoutv: Use m3u8 resolutions (single download only)
qtoutv: re-implement multi download

When downloading multiple episodes at a time, qtoutv will prompt the user
for which of lowest, average and highest quality he wants.
qtoutv: Allow download of different qualities of same episode

Fixes #33.
qtoutv: Display quality in downloads table
qtoutv: Fix some flake8 warnings
Implement Quality's __hash__ and __eq__

This allows using qualities in dicts.

This fixes, for example, being able to add the same episode with the
same quality twice to the download manager.
Merge pull request #42 from bvanheu/use-m3u8-resolutions

Use m3u8 resolutions