Fix ndindex issue

Call to ndindex() with no arguments results in a ValueError exception, whereas before commit ca27396b, a call with no arguments was allowed.
Issue is due to unneeded check for shape tuple size.
Add test for optional size argument for ndindex
Add test for __array_interface__
Fix the test for numpy.ndindex()
Fix ndindex for 0-d arrays.
Fix the 0-d patch so it doesn't change the non 0-d iterator
Use super instead of direct access to inheritance.
Fix the test for numpy.ndindex()
Fix ndindex for 0-d arrays.
Add tests for tuple arguments to ndindex
Fix 0-d ndincr to have correct return value.
Update numpy/core/code_generators/ufunc_docstrings.py
remove a confusing docstring line

ones_like:

"With default parameters, is equivalent to a.copy().fill(1)."

This is not technically true, because 'fill' returns None.
Merge pull request #2908 from argriffing/patch-1

Update numpy/core/code_generators/ufunc_docstrings.py
Fix typo in SVD usage example
Merge pull request #2910 from rutsky/doctest_svd_typo

Fix typo in SVD usage example
BUG: Convert non-array rhs for boolean assignment with correct dtype

Enforcing the left hand side datatype for a non-array right hand side
argument in index assignments was the behavior before 1.7. and is the
general behaviour here. (note this means a non-array right hand side
checks for NaN, etc. if the left hand side is integer, but an array
right hand side does not)
BUG: Make 1d fancy indexing special case use unsafe_casting

Also make sure right hand side is converted safely to the right
type if it is not an array though.
Merge pull request #2909 from argriffing/patch-2

remove a confusing docstring line
DEP: Remove scons related files and code.

This removes files and code supporting scons builds. After this change
numpy will only support builds using distutils or bento. The removal of
scons has been discussed on the list several times and a decision has been
made that scons support is no longer needed. This was originally discussed
for numpy 1.7 and because the distutils and bento methods are still
available we are skipping the usual deprecation period.
DOC: Document removal of SCons support in doc/release/1.8-notes.rst.
BUG: Need to keep SCons support in cpucaps and cpuid.

These tools are not directly related to numpy builds.