rename Gaussian models and parameters
update tests to reflect name change
rename paramdim to param_dim
rename parnames to param_names
rename psets to param_sets
remove ratio, added y_fwhm to gauss2d
Added cov_matrix option to Gaussian2D
typo in cov matrix
Add test to make a 2d gaussian with a covariance matrix
update .travis.yml to use astropy-wheels
don't install wheels for egg_info case (closes #948)
typo fix in install steps
use wheels build on 12.04-64 server
changed to all wheels all built with 12.04
added .travis.pip.wheel and switched .travis.yml to use it
clean up travis.yml tab alignment
clean up .travis.yml
removed open file detection
attempt to refresh master
added init