lame: Do not set channel mode

After further digging lame will apply the same logic based on the the
number of input channels.
lame: Set quality level to 2

Set the quality level to 2 as per recommended by the lame headers as
"near-best quality, not too slow."
Merge pull request #353 from TheRyuu/master

More lame improvements
Changed 'too long to encode' to 'high CPU usage'

This changes the terrible and vague "taking too long to encode" message
with "High encoding CPU usage!  Consider turning down settings."
Updated azubu broadcast URL.