Merge branch 'master' of https://github.com/easydigitaldownloads/Easy-Digital-Downloads into easydigitaldownloads-master
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'upstream/master'
Allow email as username during login

RESOLVES easydigitaldownloads/Easy-Digital-Downloads#1827
Merge pull request #1828 from michael-cannon/master

Allow email as username during login