Not necessarily what we want to do,
but every minor revision of less seems to change how it minifies,
which produces churn.
At least this should prevent accidental churn,
as has recently been committed to master.
adds static/style/ipython.less and ipython.min.css
Which should contain minimal styling that conflicts with other CSS.
As we improve our CSS scoping and naming,
this file should eventually be enough to play nice with embedding IPython in other HTML contexts.