Added "Parallel programming with the multiprocessing library" lesson
Updated multiprocessing lesson to reflect reviewer comments
Addressed additional reviewer comments.  Ran through ispell.
Add a section on pickling
Fixed grammatical typo
Putting intermediate Python lessons into the build
Changed the order in which parallel code is described to begin with
defining the work to be done (which follows the order in the complete
example source code)
1.  Merging fixes for missing image files from @r-gaia-cs.
2.  Putting IPython Notebook stuff in a separate Makefile so it won't inadvertently trigger when doing a regular site build.
    This ensures that people who *don't* have IPython installed,
    and don't want to re-create the Markdown files for notebooks,
    won't accidentally try to do it.
First version of sklearn intro IPython Notebook
Bringing in changes on the master branch
Removed lesson number
Adding image files produced from IPython Notebooks
Added an outline

Also removed a cell
Print number of samples in the dataset
Use StandardScaler instead of scale

For simplicity just scale all of the dataset for
grid search.
see: https://github.com/swcarpentry/bc/pull/443#issuecomment-40677511
Optimize max_features instead of n_estimators

Useless to estimate n_estimators, the more the better!
Use a Pipeline to add feature scaling
Removed feature scaling, expanded acronym RMS

Feature scaling is not necessary for Decision Tree and Random Forests:
https://github.com/swcarpentry/bc/pull/443#issuecomment-41324381
Remove import of Pipeline
added conclusion