In some cases, the replacement is clearly not what is intended,
in those (where setup was called explicitly), I mostly renamed
`setup` to `_setup`.
The `test_ccompile_opt` is a bit confusing, so left it right now
(this will probably fail)

Co-authored-by: Melissa Weber Mendonça <melissawm@gmail.com>

Co-authored-by: Charles Harris <charlesr.harris@gmail.com>

As numpy is Python 3 only, these import statements are now unnecessary
and don't alter runtime behavior.

Previously, f2py loaded the type mappings from a file ``.f2py_f2cmap``
in current directory, at import time.

Make the file name customizable by adding a ``--f2cmap`` command line
option, and postpone loading the file to f2py.run_main().

Moreover, restore the default type mapping in f2py.run_main() before
loading the customizations, so that multiple calls to f2py.run_main() do
not interfere with each other. (For example, numpy.distutils calls f2py
multiple times in the same process.)

That function is nose specific and has not worked since `__init__` files
were added to the tests directories.

Use standard pytest markers everywhere in the numpy tests. At this point
there should be no nose dependency. However, nose is required to test
the legacy decorators if so desired.

At this point, numpy test cannot be run in the way with runtests, rather
installed numpy can be tested with `pytest --pyargs numpy` as long as
that is not run from the repo. Run it from the tools directory or some
such.