editbox: reset additional variables for new program

the extra selections, line count, modified line and modified list is new
variables also need to be reset when the document is cleared; also
removed an unused member variable

editbox.cpp

@@ -509,6 +509,10 @@ void EditBox::clear()
 {
 	m_ignoreChange = true;
 	QPlainTextEdit::clear();
+	m_extraSelections.clear();
+	m_lineCount = 0;
+	m_modifiedLine = -1;
+	m_modifiedLineIsNew = false;
 	m_ignoreChange = false;
 }
 

editbox.h

@@ -93,7 +93,6 @@ private slots:
 	ProgramModel *m_programUnit;	// pointer to program unit being edited
 	int m_modifiedLine;				// current line that has been modified
 	bool m_modifiedLineIsNew;		// modified line is a new line flag
-	int m_modifiedLineOffset;		// compensate for lines inserted/deleted
 	QWidget *m_lineNumberWidget;	// widget to display line numbers
 	int m_lineCount;				// total document line count
 	QList<QTextEdit::ExtraSelection>