Various doc updates#3314

Merged

gvanrossum merged 6 commits intomasterfrom

May 3, 2017

Commits on May 3, 2017

Docs for flexible Callable
Guido van Rossum
committed
Document --cache-dir=/dev/null
Guido van Rossum
committed
Document quick mode
Guido van Rossum
committed
Update usage message to the most recent one
Guido van Rossum
committed
Add some docs and an example for ClassVar.
Guido van Rossum
committed
Address code review
Guido van Rossum
committed