Run the 2to3 ws_comma fixer on *.py files. Some lines are now too long
and will need to be broken at some point. OTOH, some lines were already
too long and need to be broken at some point. Now seems as good a time
as any to do this with open PRs at a minimum.

The idioms fixer makes the following replacements.

1) int <- bool
2) comparison or identity of types <- isinstance
3) a.sort() <- sorted(a)

There were two problems that needed to be dealt with after the
application of the fixer. First, the replacement of comparison or
identity of types by isinstance was not always correct.  The isinstance
function returns true for subtypes whereas many of the places where the
fixer made a substitution needed to check for exact type equality.
Second, the sorted function was applied to arrays, but because it treats
them as iterators and constructs a sorted list from the result, that is
the wrong thing to do.

Closes #3062.

Python 3 removes the builtin types from the types module. The types
fixer replaces such references with the builtin types where possible
and also takes care of some special cases:

    types.TypeNone           <- type(None)
    types.NotImplementedType <- type(NotImplemented)
    types.EllipsisType       <- type(Ellipsis)

The only two tricky substitutions are

    types.StringType         <- bytes
    types.LongType           <- int

These are fixed up to support both Python 3 and Python 2 code by
importing the long and bytes types from numpy.compat.

Closes #3240.

In Python 3 `map` is an iterator while in Python 2 it returns a list.
The simple fix applied by the fixer is to inclose all instances of map
with `list(...)`. This is not needed in all cases, and even where
appropriate list comprehensions may be preferred for their clarity.
Consequently, this patch attempts to use list comprehensions where it
makes sense.

When the mapped function has two arguments there is another problem that
can arise. In Python 3 map stops execution when the shortest argument
list is exhausted, while in Python 2 it stops when the longest argument
list is exhausted. Consequently the two argument case might need special
care. However, we have been running Python3 converted versions of numpy
since 1.5 without problems, so it is probably not something that affects
us.

Closes #3068

This replaces python backtics with repr(...). The backtics were mostly
used to generate strings for printing with a string format and it is
tempting to replace `'%s' % repr(x)` with `'%r' % x`. That would work
except where `x` happened to be a tuple or a dictionary but, because it
would be significant work to guarantee that and because there are not
many places where backtics are used, the safe path is to let the repr
replacements stand.

Closes #3083.

2to3: apply `dict` fixer.

MAINT: Cleanup some imports involving reduce.

In Python3 `dict.items()`, `dict.keys()`, and `dict.values()` are
iterators. This causes problems when a list is needed so the 2to3 fixer
explicitly constructs a list when is finds on of those functions.
However, that is usually not necessary, so a lot of the work here has
been cleaning up those places where the fix is not needed. The big
exception to that is the `numpy/f2py/crackfortran.py` file. The code
there makes extensive use of loops that modify the contents of the
dictionary being looped through, which raises an error. That together
with the obscurity of the code in that file made it safest to let the
`dict` fixer do its worst.

Closes #3050.

Add `print_function` to all `from __future__ import ...` statements
and use the python3 print function syntax everywhere.

Closes #3078.

Because reduce has been available in functools since Python 2.6 we
can get rid of the version checks we currently have before we import
it.

Also removes some reduce related skips in tools/py3tool.py. We were
already skipping the reduce fixer so this has no effect other than
cleaning up the code.