sd html: support export of tables for Draw documents

Change-Id: I32fe35c90c08d7c87b27ad4a5c10f91c6284c4a3
tests: add XML and HTML test tools to test module

XML and HTML parsing and XPath asserts are used by many test in
sw, sc and sd modules. This commit moves this functionallity to
test module, where it is available to all modules.

Change-Id: I53ad9c45b24f4c9bf106cb58ea619002968bfeda
sc html export: HTML export test fixture & "SkipImages" test

Change-Id: I8a419f535570924d508e1ce5f0c6bb1fbdd829a7