make it possible to filter all of edd_currency_filter's output.
Merge pull request #1477 from jdevalk/patch-1

Make it possible to filter all of edd_currency_filter's output.
Add 'None' option to Products drop down
Merge branch 'master' of github.com:easydigitaldownloads/Easy-Digital-Downloads
Fix for #1438
Merge pull request #1480 from ghost1227/bugs/1438

Fix for #1438
Formatting of register-settings
Completely refactor settings API. #1484
Merge branch 'settings-refactor' into release/1.8