I edited the Vol2.tex file to remove compile error

I had had problem compiling the Vol2 file due moving some files around.  This pull should reconcile my fix with the fix on the remote develop branch.
Merge branch 'develop' of git://github.com/byuimpact/numerical_computing into develop

Conflicts:
	Vol2.tex
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.
This is a commit of some sort.
Fixed more mistakes found by students in Vol 1 lab 3.
Merge branch 'develop' of git://github.com/byuimpact/numerical_computing into develop

Conflicts:
	Python/StandardLibrary/stdlib.tex
	Vol2.tex
Merge branch 'develop' of git://github.com/byuimpact/numerical_computing into develop
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.