add source-repository to cabal
add Setup.hs
standard gitignore for haskell

Source:
https://raw.githubusercontent.com/github/gitignore/master/Haskell.gitignore
bump upper bounds on optparse and system-fileio
Update code optparse-applicative 0.11.0.0
tweaking rgrinberg's PR, and unrelated updates

optparse-applicative bound fix
Merge branch 'rgrinberg-latest-optparse-applicative-upgrade'