Better wording for some documentation
PEP8 (fixed a line too long)
Fixed some typos and improved wording
PEP8
Fixed a number of typos in doc reported by eneftci

Also made sample code better PEP8-compliant, and fixed a minor typo in
an error message.

Fixes gh-1353
PEP8
Small typos and formatting fixes
Typo fixes
Typo fixes
Minor typo fix
PEP8
Minor rephrasing
Minor typo fixes
PEP8
Typo fixes
PEP8 (+ small code simplification)
Merge pull request #1355 from delallea/minor

Minor fixes