BUG: add proper error handling when using interp2d on regular grids

fixes #1889
BUG: fix test for interp2d
BLD: add numpy requirement to metadata if it can't be imported.

This should help Buildout users.  Closes gh-3379.
BLD: add minimum required numpy version to build_requires if numpy not found.
MAINT integrate/odepack: kill dead Fortran code
MAINT: linalg.orth memory efficiency
MAINT: cluster: some clean up work

Some useless docs, comments and code in cluster.vq are removed.
Some errors in the docs of cluster.hierarchy.dendrogram are
fixed.
Fixed confusion between 'minimum' and 'minima' in docstring of optimize.basinhopping
Corrected doctest for "singular of 'minima' is 'minimum' issue"
TST: orth regression test will now fail instead of error under regression
TST: fix a number of test errors for ``test('full')`` with numpy master.
TST: ignore deprecation warnings for optimize.anneal
Merge branch 'pr/3616' into master.

Review at https://github.com/scipy/scipy/pull/3616
Merge pull request #3638 from chatcannon/basinhopping_doc

DOC: docstring of optimize.basinhopping confuses singular and plural of 'minimum'
Merge pull request #3636 from richardtsai/cluster_vq_cleanup

MAINT: cluster: some clean up
BUG: change ddof default to 1 in mstats.sem, consistent with stats.sem.

See discussion on https://github.com/scipy/scipy/pull/3458 for details.
DEP: deprecate scipy.weave in favor of https://github.com/scipy/weave

And in favor of Cython for new code of course.

Closes gh-3171.
ENH: add pdf() and logpdf() methods to stats.gaussian_kde
MAINT: minor cleanups to doc and test changes for stats.gaussian_kde.
Merge branch 'pr/3398' into master.

See https://github.com/scipy/scipy/pull/3398