Changed Lines From Pasting

In order to detect lines that may be modified of inserted text from pasting, the text that is about to be inserted from the clipboard needs to be intercepted and examined to see what is about to be inserted.  To catch the paste action, the paste function was reimplemented in the EditBox class.  The paste key sequence also needed to be intercepted, so the key press event handler was modified to also call this new paste function for the paste key sequence.

In the new paste function, a pointer to the clipboard is obtained from the static QApplication::clipboard() function.  The plain text contents of the clipboard is obtained by calling text() function.  Since the existing function for inserting a new line contained a subset of the code needed for inserting text which may contain new lines.  So this function was modified to handle more than just inserting a single new line.  This new function is called for the return key with a string containing a single new line character.

The insert text function handles determining whether the current line (before inserting the text) needs to be reported as changed, if any new lines need to be reported as inserted, and what to set the modified status of the cursor line once the text has been inserted.  Right now this function only handles a paste when there is no text selected.

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