add ipython notebook version of assignment
edit copyright notice
Added derivation of rocket equation
initial commit - ftcs explicit heat transfer in 2d
initial crack at implicit method
initial commit -- proof of concept crank nicolson 1d heat solver
add speed comparisons to difference implicit options
Added intro to implicit scheme
Added style and small edits to notebook 1, module 4
add section on boundary conditions (unfinished)
clear output, change u->T and minor language tweaks
tweak language and segue from explicit to implicit
add stencil and equation figures
add stencil for implicit schemes and continue working on implicit writeup
add figure for implicit formulas
update svg of implicit formula to flip order of indices
Finish implicit explanation and general tweaks to whole notebook

All variables u -> T.  Added several figures and explanations for how
implicit formulation works.  Change matrix formulation to something less
efficient but (hopefully) easier to understand.
add chris explanation of neumann bc
Modified example to have Neumann BC
update implicit formula drawing to reflect variable change