[PD] New external on physical modeling : msd version 0.01

[Nicolas Montgermont]

Hi list,

On the CVS the msd, standing for mass spring damper, msd2D and msd3D 
externals have been added in the nusmuk directory. These 3 objects are 
new implementations of the pmpd object by Cyrille Henry.

They are designed to easily build physicals models based on masses and 
links. All the creation, the computation and the destruction are dealt 
in one object (depending of the number of dimensions of the space 
modelised : 1D, 2D or 3D) with messages.

The source code is in C++ so you need flext to compile it. Only the 
linux version has been tested. The examples provided often use GEM to 
display structure, the "repeat" object from zexy and the "any" 
abstraction from iemlib.

I hope you enjoy this first version of msd and excuse bugs cause it is 
still in development ;-), please report back any missing behavior or 
handling of the objects.

Bye,

Nicolas