Merge multi-part WAV files

[dheshanm]

Interviews are sometimes split into multiple files. They are to be named as YYYYMMDDHHMMSS_P#.WAV. Some expectations are:

• All parts of the same multi-part interview will share the same “YYYYMMDDHHMMSS” base name.
• The ordering of the parts will be determined by the number after P:
  • E.g.: YYYYMMDDHHMMSS_P1.WAV, YYYYMMDDHHMMSS_P2.WAV
• The total number of parts will not exceed 9.

With these assumptions, these multi-part WAV files will need to be merged into 1 WAV files before sending for transcription.