ENH: Add class for reading unformatted Fortran files
Change fortran_file/FortranFile API to match suggestions.

fortran module is now hidden
Corrected tests and doctest
DOC: Fixup documentation on FortranFile

Fix spelling mistakes
Move documentation from hidden module to class
Limit line widths
Warn if using dtypes which are not unsigned for record markers
DOC: io: adjust FortranFile documentation
MAINT: clean up integer division in FortranFile
TST: io._fortran: clean up tests + hedge for windows
Merge pull request #499 from sargas/fortranFiles

ENH: io: add class for reading unformatted Fortran files