clarified dependency scopes

Signed-off-by: Igor Fedorenko <igor@ifedorenko.com>
removed plexus annotations, jsr330 should be sufficient

Signed-off-by: Igor Fedorenko <igor@ifedorenko.com>
cache and reuse the same aether connector for multiple requests

Signed-off-by: Igor Fedorenko <igor@ifedorenko.com>
cleanup: removed useless Closer

Signed-off-by: Igor Fedorenko <igor@ifedorenko.com>
don't download .md5 if .sha1 is present

this matches wagon behaviour and eliminates 1/3 of remote requests
in most cases

Signed-off-by: Igor Fedorenko <igor@ifedorenko.com>