Detox

- *sigh* replace hardcoded long description with actual content of
`README.md`

- propagate information about new location of issie tracker to PyPI

- (fix [15](https://github.com/tox-dev/detox/issues/15)) make detox
aware of new way to fetch a package in tox 3.3 - by Oliver
Bestwalter
- (fix [15](https://github.com/tox-dev/detox/issues/15)) make detox
aware of new way to fetch a package in tox 3.3 - by Oliver
Bestwalter
- (fix [25](https://github.com/tox-dev/detox/issues/25)) print out
detox version rather than tox version including detox version as
plugin, when invoking [detox --version]{.title-ref} - by Oliver
Bestwalter

- (fix [283](https://github.com/tox-dev/tox/issues/283)) detox
creates virtualenvs repeatedly and unnecessarily - by Thomas Steinke

- (fix [792](https://github.com/tox-dev/tox/issues/792)) bump tox
version constraint to <4.0 - by Pi Delport
- support and test with Python 2.7, 3.4+ - by Miro Hrončok
- fix project url to point ot github - by Neil Halelamien
- remove some unused imports - by Nir Soffer

- 406: Add support for running detox as python -m detox Thanks André
Caron (AndreLouisCaron).
- (infrastructure) add Travis CI setup. Thanks Timothée Mazzucotelli
(Pawamoy).
- add "-n NUMPROC" option to set number of processes. The default is
the number of CPUs as determined by multiprocessing.cpu_count() or
"2" if the call does not work (e.g. on py27/windows). Thanks
Timothée Mazzucotelli (Pawamoy).