First code

Some basic tools from the HPCC site have been added to the CVS repository. These include:

direct: calculate forces using direct summation

smooth: estimate field quantities using an SPH kernel

fof: find groups using the friends-of-friends technique

skid: find groups by a watershed technique

The tools are very usable as is, so feel free to grab them by CVS. Releases into the "Files" will happen as we have time.