Discretize

Minor Updates
- bug fix in MeshIO for UBC mesh (and associated test)
- deploy to pypi from appveyor, travis on tag
- cache the averaging operator

Contributors
- grosenkj
- lheagy
- rowanc1

Interpolation Improvements

implementing the bisection algorithm without the GIL. Gets rid of a lot of python overhead for speed-ups. If using Cython, might as well use it to get down to C-like code.

All of the `for` loops are executed without any calls to the python interpreter, and the bisection algorithm is equivalent to the np.searchsorted without the python overhead. Also, since we know how big the `inds` and `vals` array will be, might as well pre-allocate them.

At least 2x-3x speed on decent sized arrays.

Should address 23

Ints
- bug fix to ensure we are using ints as indices and to create numpy arrays

Utils
- Zero and Identity have a transpose

- include *.pyx files in the MANIFEST.in so they get included in the pypi distribution

- add down-sampling capability to _plot2DImage as per simpeg/simpeg537
- Changes for windows compatibility:
- `long` changed to `long long`
- Changes for appveyor testing:
- needed to cd into a different directory to do the tests
- Setup.py changes:
- Used numpy's distutils for package management
- This can now be built and installed without any special arguments to the setup.py file. For example, python setup.py build and python setup.py install
both work.
- The setup.py files within each subpackage take care of cythonizing and attaching the extensions, making the main setup.py file a little cleaner.
- This version was able to be pip installed on my Windows machine, should consider building wheels for distribution without compilation.

This should be slightly smoother to install on pypi, and is now tested on windows.

Includes meshes for:
- tensor product mesh
- cylindrically symmetric mesh
- curvilinear mesh
- octree and quadtree meshes

This is the initial prot from the SimPEG code base.