GitLab

Added a version of Platform::getPlatform() that looks up platforms by name.  Added a Context constructor that allows platform-specific properties to be specified.

Created a CudaPlatform property for specifying whether CUDA should sync or spin loop while waiting for results

(2) Changed erfc.cpp to a header file which defines missing erf() and erfc() as static functions when using VC++ but otherwise does nothing.
(3) Replaced all nonstandard uses of real() and imag() methods as lvalues; instead work directly with the complex values.
(4) Fixed a bug in TestFindExclusions which was caught by VC++'s extensive STL debug mode self-examination.

There are still problems in hilbert.c and not all CUDA tests pass.

Checked in explicit solvent implementation for Cuda platform (cutoffs, periodic boundary conditions, SETTLE)

Changed how kernels get initialized.  StandardMMForceField now has you set the 1-4 interactions explicitly.  CMMotionRemover allows the removal frequency to be set.