Error List Changes Revisited

Using a start and an end index to track changes to the error list is not sufficient to be able to reproduce the changes in the edit box.  A simple example of this is if one error inserted and one error removed.  The next effect is that one error is changed.  However, the start and end indexes will indicate that two lines were changed.

A new scheme was implemented where there is just a start index (renamed to simply change index) and a list of change operations preformed on the error list (insert, change and remove).  This will allow the edit box to repeat the operations that were performed starting at the change index.

This scheme works because as the change list is built as a program update is processed, the index of each change will be sequential.  However, while this works for single line changes (or a group of lines with a single error change), it doesn't work when multiple lines are changed (like with a multiple line insert or delete).  Too many changes operations are appended to the change list because each line of the program update change is processed individually.

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