use the original stream.
- avoid resetting capture FDs/sys.stdout for each test by keeping capturing
always turned on and looking at snapshotted capturing data during runtest
and collection phases.
The only remaining 'py.test' references are:
* those referring to the 'py.test' executable
* those in code explicitly testing py.test/pytest module compatibility
* those in old CHANGES documentation
* those in documentation generated based on external data
* those in seemingly unfinished & unmaintained Japanese documentation
Minor stylistic changes and typo corrections made to documentation next to
several applied py.test --> pytest content changes.
holger krekel
Jurko Gospodnetić
Benjamin Peterson