First version of sklearn intro IPython Notebook
Removed lesson number
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
first draft of SSH keys for GitHub lesson
Remove import of Pipeline
added conclusion
Replaced Iris example

Iris example was not clear, replaced with another example.
Added also svg and Google Docs url.

Minor changes:
* explain del rings
* removed download of dataset, just link
remove OSX specific pbcopy, remove passphrase material, explain random art image
Add GitHub Ribbon to our lessons

Backport of 9a19e91 from swcarpentry/site.

All credits to Abigail Cabunoc <abigail.cabunoc@oicr.on.ca>
for the awesome work with CSS.
In the loop challenge changed the example: 2**4 becomes 5**3.

During a bootcamp, I was staring at 2**4 and realized it is ambiguous (in the sense that 2**4 == 4**2) and thus can be confusing for students.
It is not a big deal but it is easy to fix so here it is.

NB: I'm not committing the generated md file as it seems to contain more changes (added cstyle attributes) probably due to my ipython version.
Improve CSS for GitHub ribbon

- For small screen, preserve margin.
- Use css-beautify
Merge pull request #531 from twitwi/fix-ambiguous-python-exponentiation

In the loop challenge changed the example: 2**4 becomes 5**3.
Merge pull request #447 from r-gaia-cs/github

Add GitHub Ribbon to our lessons
In the novice shell lesson 03-pipefilter, changed sort to sort -n. In the lesson , the "sort" command is used to demonstrate sorting line counts. The lesson as written does not produce the given output on the bash shell (but does on Mac OS X terminal). By adding the -n to sort, the example should behave the same across all platforms.
Fix issue when building book

When try

    $ git clean -xdf
    $ make site
    $ make book

the HTML version of book will not be create.

This problem is fixed adding a few new rules.