As per swcarpentry/lesson-template#140, but only the core CSS
changes.

-   Remove extra space before title of boxes
-   Remove background color of boxes when printing
-   Add "Input", "Output" and "Error" tips for code blocks
    when printing
-   Avoid duplicate lines

and "learning objectives" box.

~~~
$ for file in $(grep -r -l 'bootcamp' .); do sed -i 's/bootcamp/workshop/g' $file; done
$ for file in $(grep -r -l 'boot camp' .); do sed -i 's/boot camp/workshop/g' $file; done
~~~

and others minors changes.

Close #240.

The CSS was add at our main CSS and remove from printing:

- Logo at header
- GitHub ribbon
- Footnote

Close #561.

**Note**: This is a prototype.

Instead of "In" and "Out" use arrow to mark the input and output
of IPython lessons.

To construct the arrows we only use CSS.

When using large font it will overflow the width so I add
max-width in the css.

The 'box' class overflow the window width for some screen size.
This patch fix it using CSS media query.