Sequencing Patterns edits

This pull request includes changes to the "Sequencing Patterns" chapter/introduction.

One day (next time I get updates from your master version!), I will remember to rebase instead of just merging comments and then hundreds of changes won't show up in my pull requests... so sorry about that!

I only had a couple of changes to "Sequencing Patterns". The only item of note is that "facade" can also be spelled "façade", but the former had 13,000,000 hits on Google when I checked (and sounds more down-to-earth) and the latter had only 9,000,000, so I left it as-is.