D18434: exiv2extractor: add support for bmp, gif, webp, tga

[Friedrich W. H. Kossebau]

kossebau added a reviewer: Dolphin.

REPOSITORY
  R286 KFileMetaData

REVISION DETAIL
  https://phabricator.kde.org/D18434

To: kossebau, #baloo, #dolphin
Cc: kde-frameworks-devel, ashaposhnikov, michaelh, astippich, spoorun, ngraham, 
bruns, abrahams