Remove architecture chapter from the print version, leaving in PDF version

[Richard Murray]

In discussion with Karl on 8 June, we are considering having the Architecture chapter of the book appear only in the PDF and online versions of the book. The idea is that the printed version should remain compact and this material is of a different flavor: no exercises and a bit more expository. We can have it show up as a "bonus" chapter in the PDF version of the book (including the iPad version) as well as a separately downloadable chapter from the main contents page.

[Richard Murray]

This has been implemented. The \ifonline macro is used to include the architecture chapter and this is set to true for online versions of the text.

There is also an onlinetext environment that can be used to selectively include text that is only in the online version (eg, references to the architecture chapter).