Revise intro.
Fix #154.
Make pattern chapters more consistent.

Added a bunch of details to the style guide for how chapters should
be formatted.
Fix #178.
Mention DI in Singleton. Fix #184.
Fix #189.
Fix #188.
Fix #195.
Fix #196.
Fix #186.
Fix #183. Fix #180.
Fix #199.
Fix #168.
russian change test
apply changes from upstream