[lammps-users] new ReaxFF implementation

For those interested in ReaxFF, there is a new USER-REAXC
package added to LAMMPS today, due to work by Metin
Aktulga (Purdue). This is a C library implementation, so
should compile easier with LAMMPS, and also be somewhat
faster - about 2x in our preliminary tests.

See the 27 Oct 10 patch for details.