Put 3 spaces after bullet points
Merge pull request #526 from DamienIrving/lesson_fixes

Some minor fixes to challenges in some lessons
updated discussion list URL

Current URL for the discussion list takes the user to a 404 page

current: http://software-carpentry.org/contrib/discuss.html
proposed: http://software-carpentry.org/pages/discuss.html
Init. commit of (medical) image processing ipynb.
Merge pull request #528 from benmarwick/fix-typo-in-contrib

updated discussion list URL
Merge pull request #514 from gvwilson/every-challenge-in-its-own-div

Put each challenge exercise in a div of its own.
*   Simplified Makefile and added documentation.
*   New and improved Windows installer.
*   Updated ggplot2 example.
*   Renamed the `aux` directory to `misc` (since `aux` conflicts with Windows filesystem conventions).
*   Added image files produced from IPython Notebooks.
*   Added climate data example as wrap-up to Python lessons.
*   Added links to how-to videos for instructors.
*   Added lesson on `doit`.
*   Added lesson on multiprocessing in Python.
*   Added `bin/swc_index_validator.py` to check formatting of bootcamp home pages.
*   Put rules for compiling IPython Notebooks into separate `ipynb.mk` Makefile.
*   Created `bin/setup-bootcamp.sh` to create and fill a bootcamp repository.
*   Removing deprecated lesson material.
*   Many small changes to lessons, glossary, formatting, etc.
Merge pull request #530 from gvwilson/gh-pages

Bringing in changes April-June 2014
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
Novice shell lesson is now written in terms of Nelle instead of Vlad.
Merge branch 'master' into creating-slides-for-lessons
Starting to rewrite intro slides
Updating introductory slides
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.
Add title to book

This will help when converting to EPUB (and probably PDF) and also
improve the text at web browsers top bar or tab.
Update template for book to rely on CSS

Use h2 tag for "subtitle" will break any tool used to convert HTML
for another format. This commit replace h2 with span and rely on
CSS for have the same look.