2to3: Apply itertools fixer.

In Python 3 zip, map, and filter are all iterators, consequently the
itertools variants izip, imap, and ifilter have been removed and the
itertools fixer replaces them with the unprefixed names.

Because the places where the iterator variants are used in current look
like places where the iterator version might be useful, the approach
taken here is to define the prefixed versions to the unprefixed versions
for Python 3, but otherwise import them from itertools.

Closes #3233.
Merge pull request #3236 from charris/2to3-apply-itertools

2to3: Apply itertools fixer.
2to3: Apply the `numliterals` fixer and skip the `long` fixer.

The numliterals fixer replaces the old style octal number like '01' by
'0o1' removes the 'L' suffix.

Octal values were previously mistakenly specified in some dates, those
uses have been corrected by removing the leading zeros.

Simply Removing the 'L' suffix should not be a problem, but in some
testing code it looks neccesary, so in those places the Python long
constructor is used instead.

The 'long' type is no longer defined in Python 3. Because we need to
have it defined for Python 2 it is added to numpy/compat/np3k.py where
it is defined as 'int' for Python 3 and 'long' for Python 2. The `long`
fixer then needs to be skipped so that it doesn't undo the good work.

Closes #3074, #3067.
Merge pull request #3232 from charris/2to3-apply-numliterals-fixer

2to3: Apply the `numliterals` fixer and skip the `long` fixer.