Catching Line Changes (New Lines)

So far the edit box is catching lines that are modified including newly inserted lines.  One of the ways that new lines are inserted is the Return key (at end of the line) or Control+Return key (splitting a line).  The edit box needs to indicate that line has been inserted and not modified, so the line changed signal was modified to report the type of change, modified, inserted or deleted.  A new function was implemented for inserting a new line into the program called for both Return keys.

When the cursor is at the end of the line, a new blank line will be inserted on the next line.  If the current line is not modified, this line does not need to be emitted since it hasn't changed.  However, if the line has been modified, it will be emitted as a modified line.  For the new blank line, all that needs to be done is the line number recorded and the new modified line type set to inserted.  The line will be emitted as a new line when the cursor leaves the line.

When the cursor is in the middle of the line (splitting the line), the line will be emitted since it is being truncated.  For the new line, the end part of the line that is now on the new line, the line number is recorded and the new modified line type set to inserted.  The line will be emitted as a new line when the cursor leaves the line.

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