fate: Use bitexact conversions in the dpxparser test

This fixes fate on e.g. ppc.

Signed-off-by: Martin Storsjö <martin@martin.st>
dashenc: Fix writing of timelines that don't start at t=0

When writing an explicit time, reset the cur_time variable to this
value as well. This avoids writing excessive time attributes for each
segment in the timeline, as long as the segments are continuous.

Signed-off-by: Martin Storsjö <martin@martin.st>
dashenc: Remove some stray double spaces

Signed-off-by: Martin Storsjö <martin@martin.st>
dashenc: Use pts for MPD timestamps

This should be more correct. This also should give more sensible
switching between video streams with different amount of b-frame
delay.

The current dash.js release (1.2.0) fails to start playback of
such files from the start (if the start pts is > 0), but this has
been fixed in the current git version of dash.js.
sidxindex: Don't adjust the Period start time depending on the track start time

This was only necessary to get playback to start with dash.js 1.2.0,
it has been fixed in the git version.

The previous behaviour was incorrect - the Period's start time
is irrespective of the actual first timestamp of the contents
within the period. The Period start time only says when, within the
global timeline, this particular piece should start to be played
back.
sidxindex: Remove parsing that isn't necessary any longer

When we don't adjust the Period start time, we don't need to
parse the earliest_presentation_time from the sidx boxes either.