GitLab

- MingW, where "WIN32" is set by CMake but the compiler is not Microsoft's (should use _MSC_VER) in that case, and 
- in gcc 4.4 which is fussy about some issues that earlier versions were silent about, such as passing a string constant to a "char*" rather than a "const char*".
I also fixed a syntax error in CMakeLists that showed up in the OpenMM workshop for some unknown reason.

Brook is not currently building correctly; I think it has not yet been fully converted to the getTime() interface needed for variable step integrators.

Optimization to constraint algorithm: skip the last iteration as soon as we see that all constraints have converged.

Eliminate some VC++ build problems via the usual expedient of explicit casts from unsigned to signed and from double to float. TNT Arrays apparently can't be indexed with unsigned because VC++ finds something ambiguous then above their operator[] methods.

(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.

Implemented setting random seed for reference platform, as well as adding it as an option to BrownianIntegrator and AndersenThermostat.