">>>" in code snippets

[EGaraldi]

In the tutorial, some of the code snippets provided have the code prepended by ">>> " making it hard to copy-paste the code into the terminal.

[cbyrohl]

I would still favor pycon mode (implying the use of ">>>") to reduce number of code cells (i.e. splitting input and output), as done in e.g. the scipy user guide). We can manipulate the css to never select the ">>>" when manually copy & pasting using the mouse selection, see here, to make the copy-paste more hassle free. Unfortunately, this will not be possible for the copy&paste button (see here), so I deactivated the button for pycon cells in cdc57b9