average-bandwidth and frame-rate attributes added as known ones

[astroza]

Hi,

I added 2 known attributes 'average-bandwidth' and 'frame-rate' to stop messages like this:

Handling value: 2890800 for unknown key: average-bandwidth Handling value: 30.000 for unknown key: frame-rate Handling value: 1240800 for unknown key: average-bandwidth Handling value: 30.000 for unknown key: frame-rate Handling value: 965800 for unknown key: average-bandwidth Handling value: 30.000 for unknown key: frame-rate Handling value: 5090800 for unknown key: average-bandwidth Handling value: 30.000 for unknown key: frame-rate

on manifest parsing