Use PCA on cross and auto correlations

Address issue #80

Use PCA to cluster crosscorrelations and autocorrelations. PCA on
different types of microstructures still needs work.
Add MKSKernelPCAModel and make_microstructure

Address issue #80

Add MKSKernelPCAModel. Model takes in a microtructures with dimensions of
(n_samples, Nx, Ny,...) computes spatial correlations and does kernel
principle analysis on the correlations.

Add make_microstructure to provide a convenient interface for
microstructureGenerator.

The microstructure generator is currently partitioning an equal number of
bins for what looks like a normal distribution. It should equally partition
the cumulative distribution. A MKSKeneralPCAModel example still needs to be
made.
Update model, methods, and functions to match python style guides

Address issue #80

Update model, methods, and functions to match python style guide except for
those that mimic those from sklearn.
Update examples with new python style guide API

Address issue #80

Update examples with new API from python style guide. Warning outputs need to
be handled before suppressed before documentation can be updated.
Update method and function naming convention

Address issue #80

Update method and function naming conventions to meet python style guidelines.
Update notebook examples with new API

Address issue #80

Update notebook examples with new API that came as a result of meeting python
style guidelines.
Merge branch 'issue80-spatial-statistics-example'

Fix #80
Merge branch 'master' into release-0_1

Conflicts:
	notebooks/elasticity_2D.ipynb
	pymks/__init__.py
	pymks/datasets/__init__.py
	pymks/datasets/cahn_hilliard_simulation.py
	pymks/datasets/elastic_FE_simulation.py
	pymks/tests/test.py
	pymks/tools.py
Clean up after merging master

Address #82

 * Remove left over merge conflicts.

 * Eradicate spurious use of underscores in class names and file
   names. If the class is instantiated somewhere then it shouldn't
   have an underscore.

 * Make tests pass as they were not checked on previous merge.
Clean up all notebooks for release

Address #82

The notebooks have been improved so that

 * references are just links, not explicit

 * use of [i] notation consistently

 * remove use of $h$ notation for anything but an index over state
   space

 * improve all written descriptions

An additional major change a rewrite of the description of the
Legendre basis so that

 * it that there is a direct comparison between the continous
   indicator and Legendre

 * consistent notation, $h$ is only an index.

 * demonstrate the mapping between the $m_h$ and $\phi$ for both bases
   which was previously unclear