writerfilter: remove strange SAL_DEBUG lines

Ideally the git hook makes impossible to add these.

Change-Id: Ifa06ddde41ad4f23368ae401c1aa58a43fd14e12
SwXTextField::getAnchor: avoid pointless dynamic_cast<>

Change-Id: I4cc96b8e1dee423216e528410953108c64ac5d63
CppunitTest_sw_mailmerge: remaining MM methods from header file

Change-Id: I74e5ebd0d879ce6864707b28b002672e5fb78f74
Use oox::drawingml::convertHmmToEmu()

Change-Id: I0ee90069eaf626e84f3b2b84d10be09a0f5b1561
Use oox::drawingml::convertEmuToHmm()

This makes the +1 hack unnecessary in CppunitTest_sw_ooxmlexport2.

Change-Id: Ibf0a32b0bf03e9b47850edb335947e4ec383327b