[Pytest-commit] Issue #139: tox 1.6.1 uses default pip 1.3.1 -> bad install_command default (hpk42/tox)

[freeo]

New issue 139: tox 1.6.1 uses default pip 1.3.1 -> bad install_command default
https://bitbucket.org/hpk42/tox/issue/139/tox-161-uses-default-pip-131-bad

freeo:

Tox 1.6.1 doesn't work out of the box using win32, python33 32bit.

The install_command default is `pip install --pre ...`, which is unsupported by `pip 1.3.1` - the version, which gets installed by tox! I didn't find a possibility to set `deps=pip>=1.4.1`, which leads to a circular problem, if I want to avoid changing the default `install_command`! I can't upgrade pip without changing the default. Upgrading itself make the change obsolete. 
The default pip version for any environment should therefore be `pip>=1.4`, if the `--pre` option is a default!
This was annoying to find for a newbie like me...

This is my working tox.ini, just in case.

```
#!tox

[tox]
envlist = py33
[testenv]
install_command=pip install {opts} {packages}
deps=
    -rrequirements.txt
commands=
    py.test
[testenv:py33]
basepython=D:/Python33/python.exe
```

requirements.txt:  
`pytest`