Added todo to find frame anchor-types from the style tree

Frames that have no direct anchor-type specified currently have incorrect
behaviour, as these default to not behaving as character frames. The
correct behaviour is to actually examine the style inheritance hierarchy
to find the parent style that sets the default.
Merge pull request #176 from peitschie/cursor-positions

Added todo to find frame anchor-types from the style tree
Move API dox for core.UnitTest
Inject profiling into op execution
Small cleanup to cursor insertion logic

Don't need to walk through each sibling to find the correct offset.