Save Image-Crop information in docx

Issue:-
1] When MS Office docx file containing cropped image is
   round tripped with LibreOffice 4.2, image looses
   its cropping effect.

Implentation:-
1] Function WriteSrcRect() is implemnted inside docxattributeoutput.cxx
2] It writes out xml tag <a:srcRect> which is responsible for storing
   cropping parameters
3] Written Unit Test to verify cropping parameters

Conflicts:
	sw/qa/extras/ooxmlimport/ooxmlimport.cxx
Reviewed on:
	https://gerrit.libreoffice.org/6240

Change-Id: I6ab30305bae44ca1bfef73b0df2967d943ee60fe