BUG: fftconvolve should raise error for invalid mode instead of doing nothing
DOC: the type of `exact` parameter
`comb` support combinations with repetition
add tests for comb
add `perm` function
Add scale_pcov argument to scipy.optimize.curve_fit
ENH: optimize/curve_fit: rename scale_pcov -> not absolute_sigma
TST: optimize: add test for curve_fit pcov scaling
add tests for `perm`
fix tests fail
some cleanup
fix tests fail
BUG: optimize: return a matrix if indeterminate variance

The documentation says pcov is a matrix, so it may be confusing to have
it be a scalar in some pathological cases.
MAINT: avoid DeprecationWarnings with numpy 1.7 in stats tests
MAINT: remove kolmogorov_check, duplicated test

* kolmogorov_check is not run, superseded by check_distribution
* remove docstrings from tests
* remove one of the two copies of check_edge_support
TST: collect entropy tests together
MAINT: collect the moments tests together
TST: collect together the tests for support edges & out-of-bounds
TST: reenable test for _ppf not NaN

and move it to test_continuous_basic
MAINT: move regression tests from test_continuous_extra

remove test_continuous_extra as it does not contain anything useful
anymore