Merged the first two MPI labs bc they are short
And took it out of tex doc
Changed the directories
Redid line breaks in hysteresis lab.
Simplified code in hysteresis lab.
Added some hints and updated some formatting.
Fixed some typos found by students.
Modified finitevolume.tex
remove IPython Notebook recommendation + fixes

We should not be recommending the IPython notebook as the standard
interface.  While we do suggest that they use IPython, we should let
them choose their preferred environment.

Also, the IPython notebook does not work well with automated grading.

Made other various fixes.
change interactive prompt

use >>> like the rest of the labs.
rename solutions

Use the solutions.py convention.
rename lab plotting script
update prob1 figure

Latex complained that couldn't read the PDF file.
consolidate plots into single plotting script.
more reorganizing plots
removing old plots
update figures to use plotting style.
update plot pathnames
clear figure after saving each plot
update plots