TextDocumentView: Don't blink cursor when not in focus.
TextEditor: Comment on up/down behavior for first/last line.
MarkupParser: Append \n to each paragraph.
Paragraph: Added simple PrintToStream().
ParagraphLayout: Refactored _GetEmptyLayoutBounds().

Even for an empty Paragraph, some meaningful bounds can be computed when
it contains an empty TextSpan. However, this is not yet achieved, since
no LineInfo is generated for such an empty Paragraph.
TextDocumentLayout: Fixed finding the right paragraph for an offset.

It was not possible to place the cursor at the beginning of a paragraph
once they actually contain the \n at the end.
TextDocumentTest: Give the text view initial focus.
TextDocument: More fixes.

 * Handle shifting the contents of the next paragraph into the preceeding
   paragraph if text up to and including the line break of the preceeding
   paragraph is removed.
 * Fixed removing the correct paragraph in the loop when it hits the last
   paragraph. (though that code is still untested)
TextEditor: Dump the TextDocument on all edits for now.