Slightly less skanky complex_hb graph.  Still fairly skanky.
Update .gitignore a little.
Switch the alpha PDFs over to a rectangular kernel, rather than a
gaussian one, so that I can do a proper boundary correction.
Fairly major reworking of the evaluation.
Tidy up a little.
New graphs looking at behaviour with more complicated aliasing
patterns.
A whole bunch of new graph generating scripts whcih present the bubble
data in a slightly different way.
Some data for the phase_breakdown graphs.
Rejigger the artificial bug graphs in various ways.
Rename Load expressions to InitMemory expressions, since that does a
slightly better job of explaining what they're for.
Feedback from Steve.
Generally tidy up a bit.
Check in state of the world.
Make figures look a little bit nicer.
Further de-uglisation of figures.
Fix up first couple of chapters a little bit.