Update contents of module 1
quick typo fix in readme
Add BEM module, modify ketch's role.
Merge pull request #4 from numerical-mooc/phugoid_solution

Phugoid solution
ignore checkpoint
add downloadable copy of Ian Hawke's notes
strip out all but lessons 1 and 2 for initial merge
execute notebooks and check eqn numbers are sane
Merge pull request #6 from numerical-mooc/phugoid_merge

merge of lessons 1 and 2 in phugoid module to solutions
merge solutions to master - phugoid 1 and 2
Remove unused figures
Two small typos in phugoid text.
Merge pull request #9 from FrenchKheldar/FK-fixes

Two small typos in phugoid text.
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
Make text more precise when describing motion

especially when talking about the angles, we have pitch angle (positive
up), then glide angle in the force balance: a bit sloppy