python setup.py test fails if there are spaces in the directory path

(This issue was originally reported against the affiliated package template at https://github.com/astropy/package-template/issues/54 but appears to be an issue in astropy itself.)

It seems that the test framework doesn't work if there are spaces in the directory path. I ran into this because I'm using Dropbox with linked personal and work accounts so I have folders "Dropbox (Personal)" and "Dropbox (Work)". In this case my source code is in a folder inside "Dropbox (Personal)", and when I try to run the test suite from setup.py, it fails. See below. I'm not sure if this is a problem in the astropy helper infrastructure, or if it's an upstream problem.

Interestingly this works just fine if I run my package's test() function from inside Python. The failure only happens when I try invoking it from setup.py.

(More generally: yes, I agree it's obnoxious that Dropbox is now forcing its users to deal with path names that have spaces and parentheses in them. We've complained to them about that already too. )

```
mperrin@mperrin ~/Dropbox (Personal)/software/astropy > python setup.py test
running test
running build
running build_py
copying astropy/wcs/include/wcslib/cel.h -> build/lib.macosx-10.6-x86_64-2.7/astropy/wcs/include/wcslib
copying astropy/wcs/include/wcslib/lin.h -> build/lib.macosx-10.6-x86_64-2.7/astropy/wcs/include/wcslib
copying astropy/wcs/include/wcslib/prj.h -> build/lib.macosx-10.6-x86_64-2.7/astropy/wcs/include/wcslib
copying astropy/wcs/include/wcslib/spc.h -> build/lib.macosx-10.6-x86_64-2.7/astropy/wcs/include/wcslib
copying astropy/wcs/include/wcslib/spx.h -> build/lib.macosx-10.6-x86_64-2.7/astropy/wcs/include/wcslib
copying astropy/wcs/include/wcslib/tab.h -> build/lib.macosx-10.6-x86_64-2.7/astropy/wcs/include/wcslib
copying astropy/wcs/include/wcslib/wcs.h -> build/lib.macosx-10.6-x86_64-2.7/astropy/wcs/include/wcslib
copying astropy/wcs/include/wcslib/wcserr.h -> build/lib.macosx-10.6-x86_64-2.7/astropy/wcs/include/wcslib
copying astropy/wcs/include/wcslib/wcsmath.h -> build/lib.macosx-10.6-x86_64-2.7/astropy/wcs/include/wcslib
copying astropy/wcs/include/wcslib/wcsprintf.h -> build/lib.macosx-10.6-x86_64-2.7/astropy/wcs/include/wcslib
running build_ext
skipping 'astropy/table/_np_utils.c' Cython extension (up-to-date)
skipping 'astropy/time/erfa_time.c' Cython extension (up-to-date)
skipping 'astropy/convolution/boundary_extend.c' Cython extension (up-to-date)
skipping 'astropy/convolution/boundary_fill.c' Cython extension (up-to-date)
skipping 'astropy/convolution/boundary_none.c' Cython extension (up-to-date)
skipping 'astropy/convolution/boundary_wrap.c' Cython extension (up-to-date)
running build_scripts
============================= test session starts ==============================
platform darwin -- Python 2.7.6 -- pytest-2.5.1

Running tests with Astropy version 0.4.dev8738.
Running tests in astropy /Users/mperrin/Dropbox (Personal)/software/astropy/docs.

Platform: Darwin-10.8.0-i386-64bit

Executable: /Users/mperrin/software/macports/Library/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/Python

Full Python Version:
2.7.6 (default, Dec  3 2013, 14:14:54)
[GCC 4.2.1 (Apple Inc. build 5664)]

encodings: sys: ascii, locale: , filesystem: utf-8, unicode bits: 15
byteorder: little
float info: dig: 15, mant_dig: 15

Numpy: 1.8.1
Scipy: 0.12.0
Matplotlib: 1.3.1
h5py: 2.2.0

plugins: cov
ERROR: file not found: (Personal)/Documents/software/git/astropy/docs

===============================  in 0.08 seconds ==============================
```