use C++11s range-based for() loops instead

Conflicts:
	sd/source/filter/eppt/pptx-epptooxml.cxx

Change-Id: I0868eb345932c05b7e40b087035da252b99bf0b9
Reviewed-on: https://gerrit.libreoffice.org/13714Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>