BUG: fix complex norm of higher order

asfarray truncates the complex part, so it must be avoided for complex
types.
Closes gh-4156.
DOC: move f2py documentation under doc/ and link its user guide with Sphinx
DOC: fix up f2py user guide formatting
DOC: split up f2py user guide + markup fixes
DOC: f2py: Numeric -> numpy
MAINT: remove unused file
DOC: f2py: minor fixups
DOC: f2py: update numpy.distutils part a bit
DOC: f2py: more Numeric -> numpy updating
DOC: f2py: fix some typos etc
Merge pull request #4168 from pv/f2py-docs

DOC: Move f2py docs under doc/ and link to Sphinx docs
Merge pull request #4163 from juliantaylor/complex-norm-fix

BUG: fix complex norm of higher order