- plugin callbacks now draw their stuff until run/cancel is executed (so we
  manipulate the scene with the additional data displayed)
- made plugin code much shorter
- simpler defaults for StreamLines, CutGrid and Evaluate

draw points instead of grid

add callbacks to draw grid + fix interval definition

add callbacks to draw grid

fixed typos + option file location for new Min/Max options

new Plugin(Probe) to query the value of a view at a single point

new Plugin(Remove) to selectively remove parts of a view (e.g., all
the text strings, all the scalar lines, etc.). Very useful to clean up
maps after cuts, or to reset comment strings.

- new alternative Draw_String function taking a "style" argument (used
  only for font size at the moment)
- new Plugin(Annotate) to add simple text strings to a view

set num of rotor/stator teeth as parameters

more robust "Delete Empty Views"

my last commit also fixed several problems in For/EndFor loops:

- the body of the loop was executed at least once, even if the test was
  always false (e.g. For (1:-1:1) )
- the body could be executed one extra time when using optional
  step values
- the for loops didn't work with negative step values

- new parser function GetValue("text", default_value) to query a value
  interactively in a script

- added a nice example using this (to compute slices automatically):
  demos/multislice.script

- new "Delete Empty Views" command
- new View.MinX, View.MinY, View.MinZ, View.MaxX, View.MaxY, View.MaxZ options
- added example on how to do simple volume visualization

better help messages

fix widget position

add color options for elements in views (requested by Philippe a long
time ago)

power law for the alpha channel

add matlab colormaps: hsv, bone, spring, summer, autumn, winter, cool, copper

missing viewchanged=1

typo

add all remaining colormap parameters as options

make the middle button zoom more progressive (+ add acceleration factor
in the GUI)

- new colormaps (jet, hot and pink from Matlab) + generalized
  handling of grayscale colormap

- new View.Colormap option (this enables Gmsh to remember which
  colormap to use or which colormap the current modified colormap
  comes from) + better View.AlphaChannel treatment

- fix saving of color options when color_scheme is != 0

added File->Rename menu

We cannot use _quad as a class name: gcc 2.95 uses it internally

fixed "gcc -pedantic" warnings

Patch from Andreas Jochens so that 'gmsh' can be compiled on amd64
using gcc-4.0.