allow mpd url in query string

index.html?mpd=<mpd url>
This will immediately load the specified mpd url
add getBufferRange
added tfinish to the HTTPRequest metric
use tfinish in the DownloadRatioRule
fixes seek issues and expands logging output
fix regression in main usage scenario
Fix initial seek logic and pause/play bug

seek back, then pause then play would reset the playback to the start of
the content.
fix timescale defaults to prevent NaN