Provide row / column of caret position as ready only properties

[svenreimers]

For using rta as a code editor, you want row / column information to be display e.g. in a status bar. This needs acces to inner information of the rta.

[jperedadnr]

@svenreimers PR submitted, hopefully this will provide the information that you were requesting?

[johanvos]

@jperedadnr can you add a test?

[svenreimers]

@svenreimers PR submitted, hopefully this will provide the information that you were requesting?

Looks good - not sure about the paragraph implication but feels ok.