Move location of default ``astropy.cfg`` file to root of source tree (rather than in config), and make it possible for affiliated packages to generate configuration files too.
Fixes #672.  Long ints are not handled correctly in Unit constructors.
sigma_slip was moved to stats -> change docstring accordingly
Fixed path to astropy.cfg in .gitignore
Merge pull request #688 from astrofrog/config/fix-config-file-affiliated

Fix generate_default_config to work with affiliated packages
Merge pull request #698 from hamogu/docutypo

sigma_slip was moved to stats -> change docstring accordingly
Merge pull request #672 from mdboom/unit/long_int_handling

Unit conversion on quantities mishandles long values
Merge pull request #699 from eteq/travis-yml-split-optionals

Hide log for dependencies installs in travis
make travis run tests with remote data