Merge pull request #221 from peastman/master

Fixed bugs in computing PME energy with CPU platform
Merge pull request #222 from peastman/master

Optimization to building neighbor list on CPU platform
Merge pull request #223 from peastman/master

Optimizations to CPU nonbonded forces: better load balancing between threads, use linear splines instead of cubic
Merge pull request #224 from peastman/master

Enforce memory alignment to improve performance of vector operations.  Also fixed bugs in an earlier optimization.
Merge pull request #225 from peastman/master

More fixes for problems on OS X 10.9
Added implementation for equality __eq__() and inequality __ne__() operators
Merge pull request #228 from peastman/master

Minor optimizations to CPU platform
Check type in __eq__() and __ne__(), simplify code
Merge pull request #229 from peastman/master

Further optimizations to CPU platform
Merge pull request #230 from peastman/master

Major simplification to constraint handling in reference platform
Merge pull request #227 from pgrinaway/units

Implemented equality and inequality operators for BaseDimension
Merge pull request #231 from peastman/master

Parallelized SETTLE on CPU platform