Recapture focus after clicking on an already selected image

Clicking on a selected image will lose the event trap focus. Focus needs
to be restored back to the event trap after this.
Recapture focus after deleting an annotation
Merge pull request #313 from peitschie/recapture-focus

Recapture focus after clicking on an already selected image
Use NodeFilter.SHOW_ALL instead of value constant everywhere
Fix parameter annotation for getAppliedStylesForElement of Formatting.js
Preserve the text style when splitting at the end of paragraph.

At the moment, splitting at the end of the following paragraph
<p style-name="standard">hello <span style-name="bold">world|</span></p>
will create a new paragraph like below
<p style-name="standard">|<span style-name="bold"></span></p>

The cursor is moved out of the span due to empty span is not considered as
a valid cursor position in the current design. this causes newly entered
text are not formatted correctly.
Merge DirectTextStyler.js and DirectParagraphStyler.js into DirectFormattingController.js
Pass down the directParagraphStylingEnabled flag to DirectFormattingController.js, disable the paragraph related methods if the flag is true.