Added option for setting CUDA host compiler
Add a salt concentration term to the custom GB forces and add an optional
"kappa" keyword to the Amber createSystem method call to allow users to specify
it.
kappa -> implicitSolventKappa
Merge pull request #253 from peastman/master

Bug fixes
Merge pull request #254 from peastman/master

Parallelized LangevinIntegrator for CPU platform
Merge pull request #255 from peastman/master

Parallelized summing the forces from different threads
Fixed quotes in command line when using CudaHostCompiler option
Allow implicitSolventKappa to have units (it has dimensions of length) and
convert the number to pure nanometers before using it in the GB code.
Merge branch 'master' of https://github.com/SimTk/openmm
Oops, 1/length, not length.
Unit-ify the 0 in implicitSolventKappa.
Merge pull request #249 from swails/master

Add a salt concentration term to the custom GB forces
Bring GBn2 into the simtk.openmm.app namespace. Also remove some redundant
references.
Apparently 1/u.nanometers is a quantity rather than a unit, so the command:

implicitSolventKappa = implicitSolventKappa.value_in_unit(1/units.nanometers)

will always fail. The only solution I've found is to take the unit of the
quantity. i.e.:

implicitSolventKappa = implicitSolventKappa.value_in_unit((1/units.nanometers).unit)
Merge pull request #260 from swails/master

Add GBn2 to the simtk.openmm.app namespace and correct unit handling of implicitSolventKappa
Added missing required kernel names (ApplyConstraintsKernel and VirtualSitesKernel) to check for platform capabilities, since these kernels are initialized in the next code block.
Merge pull request #268 from jchodera/minor-context-fixes

Added missing required kernel names to check of platform capabilities.
Merge pull request #270 from peastman/host

Added option for setting CUDA host compiler
Merge pull request #271 from peastman/master

Workaround for compilation error on some compilers
Merge pull request #272 from peastman/master

Fixed some bugs identified by Valgrind