#281 Text version support for all text formats

[Allan Cunliffe]

Xena Stable v5.0.0 and Xena Testing (ref-3221583)

Xena is not creating text versions for some text-based formats:
* CSV
* TSV
* XML
* Powerpoint (pptx, ppt, pot)
* ODF (odp, sxi, stw)
* email (mbx, msg, pst, trim, mbox)
* MS project

Images:
* otg
* xpm
* ODF drawing

Also, nothing in archive files is being extracted for the creation of text versions.

This means that any text search facility we implement in DPR will miss content contained in the above formats.

[Allan Cunliffe]

Please ignore my inclusion of the xpm file type - see Bug 3280291 for more details