Minor change to first numpy lab.
Fixed example code in first Numpy Arrays lab.
Merge branch 'develop' into student_edits
A couple of student edits.
Merge branch 'develop' into student_edits
fix solution for binary_gray

I'm not sure what binary_gray was doing, but I don't think it was doing
it right.  It should work now as intended.

Also fixed spelling of Gray.
Fixed more mistakes found by students in Vol 1 lab 3.
Fixed small typo in matplotlib lab.
Merge branch 'develop' into student_edits
Made some edits to the vectorization lab.
update solutions

The QR was incorrectly calculated.
reorganized QR explanation

Added a problem to use QR to calculate the determinate.
revisited least squares with QR.

Use triangular solver instead of inverting R.  Updated solutions.
Merge branch 'develop' of https://github.com/byuimpact/numerical_computing into develop
Made minor edit to the affine invertible transformations lab.
rename QR tex file
talk about pivoting
add QR least squares problem

Use QR decomposition to computer solutions to least squares problems.
remove section on pivoting

Also added comments to solutions file.
Merge pull request #324 from ayr0/qr

Added problems related to QR and least squares using QR.