Fix headers

This does some maintenance work on the numpy headers. The details are in the commit comments, but generally some rearrangement is done, outdated comments removed, hard tab removal, and such. There are some new unprefixed macros added to the noprefix.h file just in case, and npy_config is fixed so that the macros used are defined and duplicate code removed.

There are some files including config.h directly that also need fixing, but that is deferred to a later PR.