2to3:DEP: Remove interactive setup and gnu compiler configuration.

These havn't been deprecated, but I think few have heard of them, much
less used them. Before this change, running setup.py without any
arguments would result in interactive help. This patch removes that
interactive help and lets setup print its usual list of commands and
options.

All the script uses of the numpy/distutils/fcompiler compilers look
quite broken to me, but I have tried to maintain compatibility with the
earlier version of gnu.py after the removal of `raw_input`.

These removals solve an incompatibility between Python3 and Python2.
The current interactive setup help uses `raw_input`, which has been
removed in python3 and replaced by `input`.  However, python2 already
has an `input` that has different semantics.  Rather than deal with
this, I think it simpler to keep both `raw_input` and `input` out of
numpy.

Closes #3063
Closes #3079
Merge pull request #3120 from charris/2to3-remove-raw_input

2to3:DEP: Remove interactive setup and gnu compiler configuration.