Assorted updates to chapter 2.

These are mostly to fix minor typesetting errors and make the text slightly more readable in places.
Make latex run 3 times by default.

Needed to get all the resulting PDF cross-references right.
Change rendering of '=>', chapter 3 updates.

Added a definition \resultingin that typesets the => (\Rightarrow) with a bit more space to make it obvious separate from either side.  Various updates to chapter 3 (data types) to tidy up typesetting;  also changed/added the odd sentence here and there to clarify and/or improve readability.
Small updates to chapter 4 for typesetting/etc.
Merge pull request #8 from nuked/master

Assorted updates for typesetting, readability and clarity.