Improvements and Wideband mode support.

* Now .decode() receives an additional argument
to specify the segments, being the first the audio
stream.
* SpeexEncoder.quality_bits still remains but no longer is
used.
* Wideband mode support.
* speex_packet_to_header breaks most of the times. So
Speex.parseHeader comes to rescue it it fails. Most of times I
try to use whatever speex provides.
* Ogg constructors receives an additional option "file" so that
the ogg stream data is all the pages instead of the first two
being headers and the remaining data.
Demo app (small) refactor

* Fixing metrics CSS for mobile
* Update Speex.JS
* Added new "audio.js" for decode wrapper
and audio element URL replacement.