These include spelling/grammar fixes, removing some outdated prose,
updating some superseded prose, and adding/cleaning up some links.
Also rewraps the entire file at 79 columns.
Badges are small images which gives the status of the Travis CI and
the coverage percentage of Codecode. It helps to check the status of
the Travis CI and to get the link to Travis CI.
See also https://shields.io/
Zachary Ware
Ned Batchelder
Victor Stinner