First pass at normalizing novice shell files
Finished getting all the right files together
Finished making text match filesystem
dotfiles still show up in the find exercises
Updated diagrams to match text
Miscounted - it's still seven directories.
Some fixes suggested by @claresloggett
Remove description of strides from novice Python 01

The current section on slicing is already relatively long. Since
we don't use strides anywhere else in the novice Python material
this removes them to avoid overwhelming the students with too much
detail too early.
Updating markdown version of 01-numpy
Remove reference to strides in natural numbers exercise

The ability to skip over count in numbers other than one isn't necessary
for the exercise, so this presents the minimal amount of information
that the student needs.

This also allows us to remove discussion of strides from the discussion
of indexing in the 01 notebook letting us minimize the amount of extra
material we are delivering.
Added missing dir spotted by @claresloggett
Fixed challenge in 05-defensive.ipynb where example function was not formatted correctly
Updating .md files generated from notebooks
first pass on novice r reference sheet
re-ordered sections to follow python, still have R specific
removed bad-mouthing loops
deleted extra line
fixed code tags, contition, data frame spelling, update packages
parameters to arguments
spelling mistake, moved string split with str concatenation