Version 3 of scrolledtext

Docs can be found at

• http://incrtcl.sourceforge.net/iwidgets/iwidgets/scrolledtext.html and
• http://purl.org/tcl/home/man/iwidgets3.0/scrolledtext.n.html

Marty Backe's example of displaying a file in a text widget:

 package require Iwidgets
 iwidgets::scrolledtext .t
 pack .t -fill both -expand true

 set filename "readme.txt"
 .t import $filename end

HJG 2016-02-07: It looks like there are problems with Iwidgets.

With tcl 8.6, this example just crashes.
With tcl 8.5, it crashes when the file doesn't exist.