rootpy/rootpy — pull request #23 by cdeil (2012-06-15 09:20:32+00:00)
Title: Better help from setup.py when root-config not found.

Print useful help when user didn't activate her ROOT installation before installing rootpy.

Before the output was a traceback that required looking into the setup.py file to understand the problem:

```
$ python setup.py install
Traceback (most recent call last):
File "setup.py", line 30, in
stdout=subprocess.PIPE).communicate()[0].strip()
File "/usr/lib64/python2.6/subprocess.py", line 605, in __init__
errread, errwrite)
File "/usr/lib64/python2.6/subprocess.py", line 1102, in _execute_child
raise child_exception
OSError: [Errno 2] No such file or directory
```

Now it is:
```
root-config not found. Please activate your ROOT installation before the root_numpy extension can be compiled or set ROOTPY_NO_EXT=1 .
```