#334 Save as popupmenu item bugs

[Wim Deblauwe]

1) In the save as dialog for a chart, there are 3 items
in the combobox: "All Files", "PNG Image Files" and
again "All Files".

2) Another thing is that there is no message that a
file will be overwritten when using "Save as...". I do
not think that JFreeChart itself should display a
message, but there should be a method present where I
can put in my own message. (Maybe a protected method in
ChartPanel that I then can override in my subclass)

I'm using JDK 1.4.2_03, Windows XP, version 0.9.16.