Revision 2606

Updates to first chapter in cookbook -> approaching completion.
New figures added for model descriptions.
Scripts updated to use pylab/matplotlib and movie making scripts added for *.avi creation.
Still to finalise in chapter 1
- twodheatdiff model of intrusion
	-contouring

- heat refraction scripts and begin cookbook sections
	- pycad discussion
	- steady state pde discussion
	- quiver plot discussion