When the "Show Results" button is pressed or
RETURN is hit while the query textfield has the
keyboard focus, a database lookup is performed,
the results are placed in a JTable, and the window
is resized to accommodate the table.
Given a string, this method replaces all occurrences of
'<' with '<', all occurrences of '>' with
'>', and (to handle cases that occur inside attribute
values), all occurrences of double quotes with
'"' and all occurrences of '&' with '&'.