Integrator changes.
Benchmark, n-body.
More benchmark and unit test.
Testing utilities.
It compiles.
The tests pass.
Insert benchmark numbers.
CLR Benchmark.
Merge branch 'master' into TemplatizeIntegrator

Conflicts:
	physics/n_body_system_body.hpp
	physics/n_body_system_test.cpp
Readying.
Lint.
Merge pull request #100 from pleroy/TemplatizeIntegrator

Templatize the integrator and use typed quantities in computations everywhere.