#372 Some file restructuring

This pull request is just to reorganize some of the files.  In particular:
- base.py was too big, so we pulled out some of the classes into other files
- Add, Convolve, Deconvolve, AutoConvolve, and AutoCorrelate are all now in compound.py
- Shapelet is now in shapelet.py
- OpticalPSF is now in optics.py
- InterpolatedImage is now in interpolatedimage.py
- RealGalaxy is now in real.py
- AtmosphericPSF is now deprecated in deprecated/atmosphere.py
- psfcorr.py is renamed hsm.py and is no longer imported.  So using functions there require the `galsim.hsm.` prefix (similar to fits, integ, config, etc.)
- EstimateShearHSM has been renamed EstimateShear, since it now has an hsm prefix: `galsim.hsm.EstimateShear(...)`
- HSMShapeData is now `galsim.hsm.ShapeData`.
- I left the HSM part of HSMParams, but we can revisit this choice.  It's now `galsim.hsm.HSMParams`.
- Ellipse has been deprecated in preparation for Jim repurposing it in #367. 
- ellipse.py is now deprecated/ellipse.py
- The CppEllipse sections of CppShear.h are now in deprecated/CppEllipse.h
- I removed the applyTransform function.  The only place we used it was to apply the magnification/dilation.  (This was inefficient, since it involved a log and then a subsequent exp to get back to the original value.) So I added a much simpler function to SBProfile, `applyScale`, which both of these now use.
- lensing.py has been split into lensing_ps.py for the PowerSpectrum stuff and nfw_halo.py for NFWHalo.
- test_atmosphere.py and test_ellipse.py (broken out from test_shear.py) are now in a deprecated subdirectory of tests.