Get constants from libsodium by calling functions
adding check for loading darwin correctly
Add support for detached signatures
Merge pull request #8 from andreas23/master

Add support for detached signatures
Merge branch 'jvarho-consts'
Merge branch 'master' of github.com:stef/pysodium
Merge branch 'master' of https://github.com/wesyoung/pysodium into wesyoung-master
Merge branch 'wesyoung-master'
Merge remote-tracking branch 'upstream/master'