Manual updated

[Rik]

11/26/11

The new functions for 3.6.0 have been inserted into the manual in this
changset (http://hg.savannah.gnu.org/hgweb/octave/rev/5820f8ce683e).

There is now a new chapter called "GUI Development" which includes GUI
elements such as uigetfile, waitbar, etc. as well as UI-associated utility
functions such as guidata and user-defined preferences.  This, anyways, is
how Matlab also organizes this hodgepodge of functions.

In that same vein, the scripts/plot directory is getting awfully crowded
with 150 .m files.  Would it make sense to break off and create a
scripts/ui directory which has the functions currently documented in GUI
Development rather than keeping them with the plot functions.

--Rik