ENH: avoid repeated matrix inverse

The `sum_cov` term doesn't change, so it's faster to use a factorized version and solve.
ENH: Add ext parameter to UnivariateSpline call

Pass parameter to fitpack.splev to control how to handle out of range
evaluations. Added test to scipy/interpolate/tests/test_fitpack2.py.

See ticket 3557.

closes gh-3557
STY avoid unnecessary transposes in csr_matrix.getcol/row
ENH: Add ext parameter to UnivariateSpline

Pass parameter to fitpack.splev to control how to handle out of range
evaluations. Parameter ext can be passed via __init__ or __call__. Added
test to scipy/interpolate/tests/test_fitpack2.py. Tests if UnivariateSpline
call equals x ** 3 for out of range x and extrapolation modes 0 and 1.

See ticket 3557.

closes gh-3557
BUG: use correct MAXGAM in beta.c

AFAICT the correct constant is used everywhere in cephes.

Also try harder to use the best order of operations when
calculating beta from gammas.
BUG: don't try to calculate beta in betainc, just call it.

fixes gh-3761
ENH: Add ext parameter to UnivariateSpline

Pass parameter to fitpack.splev to control how to handle out of range
evaluations. Parameter ext can be passed via __init__ or __call__. Added
test to scipy/interpolate/tests/test_fitpack2.py. Tests if UnivariateSpline
call equals x ** 3 for out of range x and extrapolation modes 0 and 1.
Modify _from_tck, derivative, and antiderivative methods to use ext
parameter. __init__ of LSQUnivariateSpline and InterpolatedUnivariateSpline
now accept ext.

See ticket 3557.

closes gh-3557
ENH: orthogonal procrustes solver
MAINT: replace asarray with more specific format request
MAINT: tweak import
TST: more extensive procrustes testing
MAINT: fiddle with procrustes arrays
MAINT: add an optional return value to orthogonal procrustes and add a few more tests
TST: sparse: add explicit zeros to matrices used in noncanonical format tests
TST: sparse: dense RHS/LHS are supported in comparisons for Numpy >= 1.8, so enable the tests
BUG: sparse: fix bugs in __eq__ with explicit zeros, and fix nan comparisons
Merge pull request #3779 from ewmoore/incbet_fix

BUG: special: fix overflow problems in betainc, and improve precision of beta

Fixes gh-3761
Merge pull request #3769 from perimosocordiae/patch-5

ENH: avoid repeated matrix inverse
MAINT: avoid spurious warnings in binom(n, p=0).mean() etc

closes gh-3817
Don't claim this module does distance calculations.

Distance matrix calculations were moved to scipy.spatial.distance
a long time ago.