Added CFD Python files
Updates for numerical-mooc

    * Deleted and changed references to CFD Python
    * Added license
    * Changed style
    * Changed imports to agreed convention
Trivial missing full stops.

Some semicolons to suppress output near plots.
Changed more references to CFD Python
Added solutions to spacetime module
Merge branch 'master' into spacetime_solution (update stylesheet)
replace all 26314 with eqn envir. to enable numbering
Merge pull request #8 from numerical-mooc/spacetime_solution_add_eqn_numbers

replace all $$ with eqn envir. to enable numbering
recreate shortcut for dt that keeps getting deleted
added section on Richardson extrapolation in 3rd lesson
Remove unused figures
Two small typos in phugoid text.
Merge pull request #9 from FrenchKheldar/FK-fixes

Two small typos in phugoid text.
Added discussion on Richardson extrapolation
add note to find notebooks in wiki
add link to wiki
Fix lesson 2: removed extra m in Eq. (4)
Fix lesson 2—error in Euler scheme for phugoid eqs

The Delta t was in the wrong place for both equation (11) and (12).
Then these equations were repeated for no reason in the following
sub-heading.
Add linspace()->arange() challenge

and Pro tip to get the help pane
split cells to have headings in their own cell

plus add precision on convergence/consistency paragraph