Fixed small class reference mistake in TwoPoint.load
Added TwoPoint.add_correlator to allow addition of existing correlators.
Added BareTwoPoint class to facilitate two point calculations without propagators.
Added beginnings of effective mass function
Added bare two point to core init file.
Chnaged depth of TOC in sphinx index.rst.
Added baretwopoint and pyQCD.test to docs.
Added pyQCD.test to docs.
Added fast math compiler flag to lattice.so CMakeLists.txt
Added extra todo items
Added extra todo items
Relaxed tolerance of some propagator and update tests
Tweaked tolerance in lattice py.test file