API consistency for reset methods

[Eric Harper]

Change all reset methods to ".reset()"

[Bradley Dice]

List of non-standard reset methods:

• order/BondOrder, resetBondOrder()
• order/CubaticOrderParameter, resetCubaticOrderParameter(quat<float> orientation)
  • (this one doesn't seem to have an implementation in the .cc file, and it takes arguments which are never used)
• density/RDF, resetRDF()
• density/CorrelationFunction, resetCorrelationFunction()
• density/GaussianDensity, resetDensity()
• pmft/PMFTXYZ, resetPCF()
• pmft/PMFTR12, resetPCF()
• pmft/PMFTXY2D, resetPCF(), resetPCFPy()

[Bradley Dice]

In-progress: https://bitbucket.org/glotzer/freud/pull-requests/158

[Bradley Dice]

The C++ API now uses .reset() consistently. Next, the Python API must be changed.

[Bradley Dice]

This has been released in 0.10.