index .doc files (binary Word 97–2003)

[VicDeo]

Moved from owncloud-archive/apps#1292

we do not yet support .doc files (binary Word 97–2003).
a hack was posted on stackoverflow: http://stackoverflow.com/a/265017/828717 and
http://www.dannyherran.com/2011/02/read-word-documents-with-php-up-to-word-2003/

official MS documentation: http://msdn.microsoft.com/en-us/library/gg615596(v=office.14).aspx#UnderstandMS_DOC_ExtractText

followup to owncloud/core#162