mdcore Code

added 8-single version of the potential evaluation for SPUs, still need to test for correctness and speed.

fixed-up explicit electrostatics and added 4double and 8single potential evaluation routines.

add mainpage.h for documentation.

updated todo list and added web site contents to trunk.

minor improvements to the particle sorting in runner_sortedpair.

added explicit electrostatic interactions option for the case of individual particle charges.

tightened-up the interaction routines.

some modifications to the potentials and their evaluation.

make energy accumulation staggered to avoid drowning the result in rounding error.

made potentials linear where r < a.