Preliminar commit of hsenv to work with both name and unnamed envs
Merged master
Merge remote-tracking branch 'refs/remotes/upstream/master'
Fixed #23
Fixes #23
Use `throwError` to signal GHC tarball download errors
Use the `http-streams` package to download GHC tarballs instead of an external `curl` binary

Merge branch 'issue-23'
Merge remote-tracking branch 'upstream/master'
Making the download function multi platform