Function to compare strings and return upto the last common letter - Used by autocomplete
Extension of the QLineEdit class that catches the tab key pressed event
Changed the topic_edit to my own line edit that catches the tab pressed event - used for autocompletion
Added autocomplete when the tab key is pressed in the topic_edit text box
Sets the focus to the topic_edit textbox when the widget is loaded. I can't do this in rosplot_widget.py, since I can only set the focus of a widget once it has been displayyed and it is only displayed after the widget itself is called. Might be a work around by using a QTimer - need to investigate