new gui for plugins (much better IMHO!)

- new button under the graphic window to temporarily disable mouse
  selection (speeds-up redrawing of very large models + permits to
  rotate/zoom-in a model in selection mode even when the whole screen
  is full of selectable entities--e.g. a surface mesh)

- new "lasso" selection mode (to select entities using the same kind
  of lasso as the lasso zoom: just Ctrl+click, then drag the mouse in
  selection mode; the shortcuts are the same as for the lasso zoom)

- it is now possible to unselect entities using the middle mouse button
  (only for the creation of physicals at the moment; not sure if it's
  useful in the other cases)

- new button in visibility browser to invert the current selection
  (very useful e.g. when multiple physical entities are associated
  with a given elementary entity, in order to "peel" away the model
  when adding new physicals; cf. philou)

- changed meaning of Escape shortcut (cancel lasso or toggle mouse
  selection) + restore standard fltk Escape handling for all dialog
  windows

- updated copyright string

- new mesh label mode (coordinates); all label types are now also
  available for mesh vertices

- added option in 'Print Option' dialog to disable printing of help
  strings

- added a comment string with the date when creating a new file

- new snapping grid for adding points in the GUI

Plugin(Extract) can now also extract data from a specific time step

Generalized Plugin(Extract) so that it can also create tensor views

copyright update

- Moved all the Raise[][] stuff out of the drawing routines, and into
  Graphics/Post.cpp

- New 'generalized raise' mode (can use arbitrary expressions, possibly
  with external data sources, to raise/offset views dynamically). Original
  patch by Nicolas Tardieu. Merci Nico!

- moved the AdaptiveView stuff in its own header file

- fixed small bug in IsoSimplex (when Raise != 0)

- fixed small memory leak in Plugin/Extract (when one or more
  expressions are invalid)

This patch fixes an old design flaw in the post-processing module,
namely that we used a list of Post_View objects instead of a list of
pointers to Post_View objects in CTX.post.list.

This had many annoying consequences, in particular the fact that we
needed to be extra careful every time the list was reallocated (as
pointers to the list elements would become invalid).

I tried very hard to change the code everywhere it should be changed,
but I might have missed something. Please let me know if you see
anything suspicious (like a crash when you duplicate/remove/combine/...
post-processing views).

allow x,y,z in expressions

- the main menu is now scrollable when there are more than 25
buttons and it can handle an arbitrary number of buttons (this removes
the "100 views max in the GUI" limitation)

- the view number is now also displayed in the menu (to make it easier
to find the view when one has many many views)

- added "Remove empty views" menu item

secured most of the list_pointer accesses

generalized Plugin(Extract) so that we can also create vector views

better docs

quick generalization of Plugin(Extract): we can now extract arbitrary
combinations of the field's components

small tweaks

missing return in case of error

Added automatic documentation generation for plugins

- better file names for views created by plugins
- use the file name as a guess for view_save_{ascii,binary}

forgot to remove debug printf

typo

New plugin "Plugin(Extract)" to extract the i-th component of a field