BUG: FITPACK conditions were not properly checked in LSQUnivariateSpline.

fixes #2611
STY: PEP8 for LSQUnivariateSpline
TST: sparse: replace __numpy_ufunc__ version checks by functionality check
DOC: Updated integrate.ode doc (lband, uband)
TST: integrate: Added CoupledDecay to test_integrate.py
MAINT: integrate: Fix documentation of the ode 'with_jacobian' argument.

* Fixed the documentation of the 'with_jacobian' argument of the vode
  and lsoda solvers.
* Changed the default value of 'with_jacobian' from 0 to False.
MAINT: integrate: Eliminate some code that was repeated in the vode and zvode integrators.
MAINT/DOC: optimize: Fix a doc build warning caused by optimize.anneal.

The function 'anneal' is decorated with '@deprecate(message="...")'.
When given a 'message' argument, 'numpy.deprecate' inserts
two lines at the beginning of the docstring.  The first is simply
'anneal is deprecated!'  The second is the message.  The 'deprecate'
decorator does not add any extra spaces to the beginning of these
lines, so the docstring ends up with its first two lines being
unindented.  This breaks the convention used in the rest of the
docstring, and confuses Sphinx.

This change is a quick fix: add four spaces to the beginning of
the 'message' argument.  Then only the first inserted line is
unindented, which Sphinx handles correctly.
DOC: optimize: Tweak 'linprog' docstring to fix sphinx warnings.
BUG: integrate: Fix some issues with banded Jacobians in the ode classes.

In the vode integrator class, add a wrapper of the user's Jacobian function
in the banded case that pads the Jacobian matrix to match the size required
by the F2PY-generated wrapper.

Fix the handling of a banded Jacobian in the complex_ode class.
MAINT: integrate: a bit of clean up in some test code.
DOC: add guidelines for using test generators in HACKING

[ci skip]
Merge pull request #3966 from pv/doc-testgen

DOC: add guidelines for using test generators in HACKING
Merge pull request #3965 from WarrenWeckesser/fix-doc-warnings

DOC: Fix a few more sphinx warnings that occur when building the HTML docs.
Merge pull request #3607 from WarrenWeckesser/bjodah-master

BUG: integrate: Fix some bugs and documentation errors in the ode solvers.
Merge pull request #3962 from pv/numpy-ufunc-check

TST: sparse: replace __numpy_ufunc__ version checks by functionality check
STY: PEP8 of test_lsq_fpchec
Merge pull request #3928 from andreas-h/gh2611

check FITPACK conditions in LSQUnivariateSpline