Merge pull request #4 from sjhworkman/master

Return timestamp in nestegg_get_cue_point to support DASH-WebM seeking (from https://bugzilla.mozilla.org/show_bug.cgi?id=816726)
Mozilla Bug 822933 - Add a public function to query the presence of cues in the media.
Merge pull request #5 from padenot/master

Add nestegg_has_cues (from https://bugzilla.mozilla.org/show_bug.cgi?id=822933)
Allow values for TrackNumber > 0; map TrackNumber to external index (from https://bugzilla.mozilla.org/show_bug.cgi?id=804372