Catching Line Changes (Part 2)

There are a number of different keys that could change the position of the cursor that needs to check if the line before the movement was modified including Page Up, Page Down, Return (non-insert move to next line), Return (at end of line), Control+Return (insert new line), Left (if at beginning of the line), Right (if at end of the line), Control+Left (if at beginning of the line), Control+Right (if at end of the line), Control+Home (if not at the first line), Control+End (if not at the last line), and the list probably goes on (like simply clicking the mouse on another line).  In any case, a lot of keys to check and special conditions for many (line if at beginning of the line).

I realized there was a much easier way to catch these cursor movements by using the cursor position changed signal emitted by QTextEdit.  Therefore, this signal was connected to a new cursor moved slot in EditBox.  This slot checks if the current line has been modified (value not ‑1) and if this line number is different than the current line number of where the cursor was moved to, then the capture modified line function is called.

However, this conflicted with the current line reporting mechanism, which was previously called before the cursor was moved, but now was being called after the cursor had moved.  So instead of getting the current line (block) number from the text cursor, the current line (block) was found by calling the document's findBlockByNumber() function using the line modified variable value.

These changes work for most of the cursor movement commands, but there still some commands that are not handled properly like Undo, Redo, Control+A (Select All) after a modification, delete operations that combine lines (where the line below being joined needs to be treated as a delete line), and operations involving multiple line changes (like cutting a multiple line selection or pasting a block of lines).

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