Merge branch 'releases' into dfsg

* releases: (252 commits)
  Read README.rst for description in PYPI
  Release 0.7.1
  Update numpy/scipy requirements.
  Do not import scipy.sparse globally.
  Remain compatible with numpy 1.2
  Replace latex with simple syntax in docstrings.
  Documentation update.
  Change release name to 0.7.
  FIX: mxf --> Xinfan Meng
  Some more changelog stuff.
  More fixes for the changelog.
  Add metrics to the doc.
  Minor fixes in changelog.
  More on changelog.
  More doc on 0.7 release.
  Changelog for 0.7
  Examples cleanup: remove pl.close, it is now handled by gen_rst.
  Some more docstring fixes for mixture.
  Rename nobs --> n_obs
  Rename ndim --> n_dim
  ...