MarkupParser: Don't append line-break to last paragraph.
TextDocumentLayout: Text offset at end of last paragraph...

... now yields the last paragraph index and does not subtract
the paragraph length from the text offset.
MarkupParser: Fixed issue with last paragraph...

... when the last char of the markup is \n, it shall yield one last
paragraph that is empty (doesn't contain the \n which is still part
of the preceding paragraph).
TextDocumentLayout: Remove any extra ParagraphLayouts ...

... when adapting to changes in the TextDocument. There should be more
explicit listener support for keeping the TextDocumentLayout in sync with
the document.
TextEditor: Two style fixes.