Display versions installed after install

Name and version are displayed in a `pip freeze` like format, sorted by
name. This makes it much easier for the user to ascertain what the `pip
install` actually did.

Before:

    Successfully installed pyramid zope.interface translationstring PasteDeploy WebOb repoze.lru zope.deprecation venusian

After:

    Successfully installed:
        PasteDeploy==1.5.2
        WebOb==1.4
        pyramid==1.5.2
        repoze.lru==0.6
        translationstring==1.3
        venusian==1.0
        zope.deprecation==4.1.1
        zope.interface==4.1.1