* Create new media line for interlinear display

Includes support for playing audio file segments

This supports the following workflows:
1. Clicking the play button plays the segment.
2. Clicking the same play button, while the segment is still
playing, will stop playing.
3. Clicking a different play button, while a segment is still
playing, will stop playing the current segment and start playing
the new one.
4. While the audio is playing the user can continue to work in
the gui. If the user does something that disposes the
InterlinDocForAnalysis, then the audio will stop.

Displays begin and end time offsets and speaker name
for each audio clip.

Handles bidi and display in multiple writing systems.

Displays a no media message instead of the audio play
button/info if there is no media file.

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Co-authored-by: mark-sil <[email protected]>

Keep "No Media" message when no media filepath is specified.

Add the message "Media not found: check Info tab for file name"
for the case when a media filepath is specified but the file
does not exist.

Change-Id: Id9e1448749b39a9cebbe4f6e4db7d0bdc8731403