Fixed degenrate tets generation (oops!)

#ifdef some platform-specific stuff

Fix unsigned int warning

Better web browser command for Unix + generalized call (permit
multiple '%s').

typo

- Split File->Open into File->Open and File->New (i.e., the file
  chooser now only accepts existing files for File->Open)

- Added "Online documentation" help menu

Fine-tune system menu bar

better name for MacOS system menu bar option

Set max quality

some more mpeg encoders + params for higher quality

Better doc for Show/Hide

-histogram was broken in batch mode

Don't output STATUSxN messages in batch mode

"Curve" -> "Line"

Set vis_input::value() to "*" be default

couple of bugs from he mailing list

- Slightly reorganized the visibility browser window (the "toggle"
  behaviour in the input field was confusing)

- added Show and Hide commands in the parser to enable scripting of
  the visibility stuff

- Moved Visibility.{cpp,h} into Common/ to avoid dependencies with the
  Graphics library in the parser

Fix rare crash due to Fl_Widget::tooltip() not actually copying the
string.

Fixed bug in DecomposeInSimplex (need to set deleted non-simplex lists
to NULL)

Fixed missing exception handling for PluginManager::action() (this led to
a crash when General.DefaultPlugins==0).

Be less verbose (especially since Msg can cause race conditions in this code

- new DecomposeInSimplex plugin
- new "Combine Views" command in the parser
- cleaned up View::tranform and View::smooth (+small bug fix for SLs)
- better check for transparency sorting
- make depend
- new View.AlphaChannel option to change the transparency
  globally for a given view (instead of having to change the colormap
  by hand every time)

With all the above, we can now generate very nice (and correct)
transparent iso-surfaces:

Merge "../tutorial/view3.pos";

minIso = 0;
maxIso = 2;
nbIso = 7;

Plugin(CutMap).iView = 0;

For i In {1:nbIso}
  Plugin(CutMap).A = (maxIso-minIso)/nbIso * i;
  Plugin(CutMap).Run;
EndFor

Delete View[0];
Combine Views;

For i In {1:nbIso}
  Delete View[0];
EndFor

Plugin(DecomposeInSimplex).iView = 0;
Plugin(DecomposeInSimplex).Run;

View[0].AlphaChannel = 0.6;

Set View.ShowTime=2 to show the time value even if the view contains a single
time step..

print info in all cases

Fix name

Cleaned up the whole Include/Merge/Open mess (removed the ugly
yyin/yyname tables in the parser, made the Merge routine reentrant
+ uniformized all the INFO/STATUS messages).

This should fix a nasty side effect from this morning's
commit (wrong yynames when doing multiple merges in the same
file).

Make Merge/Save/Print/Open behave like Include, i.e., open the file in the
same directory as the main project file (if the path is relative).