Replace l with I/1 in various stage and engine names (F-1, S-II, etc)
Replace I with 1 in names of F-1 and H-1 engines

This was already correct in most places, with just these exceptions.
Replace 1 with I in Saturn I/IB

All of the instances I checked in the book had this right.
Replace I with 1 in C-1/1B (became Saturn I/IB)

Verified against the book.
Add worddiff.py to diff files while ignoring whitespace

This will be used to compare the HTML text to the OCR'd version at
http://archive.org/details/stagestosaturnte00bilsrich