New Return Key Behavior

Now that the edit box has its own key press event handler, the desired behavior of the Return key can be completed.  The Return key will only insert a new line if the cursor is at the end of line, except if the line is blank, otherwise it will just move the cursor to the next line.  The Control+Return can be used to always insert a new line.

To determine if the cursor is at the end of a non-blank line, the text cursor of the edit box is used.  The text cursor holds the position of the cursor and is also used to make selections and to modify  the document of the edit box.  Since the text cursor will probably by used for many of the new key sequences that will be implemented, a copy of it is obtained at the beginning of the key press event handler.  Any changes made to this copy won't show up in the edit box unless the edit box's cursor is updated (the textCursor() access function only returns a copy of the cursor).

The text cursor contains the functions atBlockEnd() and atBlockBegin() for determining if the cursor is at the end or beginning of the line.  For a normal text document, blocks are the same as lines.  So, if the cursor is not at the end of a block or at the beginning of a block, the cursor is moved to the beginning of the next block using the moveCursor() function with the NextBlock argument.  The modified cursor is put back into the edit box and the handler returns.

This created a problem for the Control+Return key code that created a new Return key event.  When this event came back to the handler, it went through the at end of block check and was treated as a Return key and only moved to the next line.  To correct this, the new event creation code was replaced with a call to the insertText() function of the text cursor with a string containing a new line character.  The handler then returns.

[commit 29159082ec]