Multi selection of authors should be OR not AND

[adamjonas]

When filtering by author any check box indicates an OR operand not the current status of AND

[aassoiants]

^ should then also be the same for the Source

"As a user i want to know if [string] is found in [source a] OR [source b]"

Down the road we might explore advanced search, but that's farrrrrrrrrrrr backlog