replace --library with --binary and preserve package name based on specfile

So from now assume Lib packaging by default unless Exec only package
or --binary given or pkgname.spec already exists!

testcases: ghc-hakyll.spec (hasExec), xmobar, hlint, etc

- findPkgName renamed to getPkgName since no longer redundantly
  checks for existing spec files again
- rename isBinLib to binlib
- set default Group for suse