Support for AOO40 (Windows) and 0.7 release

HI Dag,

I just hacked unoconv to find Apache OpenOffice (and older OpenOffice.org versions) on Windows.

I also decoupled the Options() argument parser from the found version, so it honors now debug
verbosity from the beginnig. With Python 3 support I propose to release a 0.7 version soon, to allow
the use of the recent Apache OpenOffice 4 or LibreOffice 4 versions.

Regards
--Volker