brian-rose/climlab: Version 0.7.2

Improvements to surface flux processes, a new data management strategy, and improved documentation.

Details:

  - ``climlab.surface.LatentHeatFlux`` and ``climlab.surface.SensibleHeatFlux`` are now documented, more consistent with the climlab API, and have new optional ``resistance`` parameters to reduce the fluxes (e.g. for modeling stomatal resistance)
  - ``climlab.surface.LatentHeatFlux`` now produces the diagnostic ``evaporation`` in kg/m2/s. ``climlab.convection.EmanuelConvection`` produces ``precipitation`` in the same units.
  - The previous ``PRECIP`` diagnostic (mm/day) in ``climlab.convection.EmanuelConvection`` is removed. This is a BREAKING CHANGE.
  - Data files have been removed from the climlab source repository. All data is now accessible remotely. climlab will attempt to download and cache data files upon first use.
  - ``climlab.convection.ConvectiveAdjustement`` is now accelerated with ``numba`` if it is available (optional)