Updating default handling of query constraints so that constraints against the same type are OR by default and constraints against different types are AND by default.

New behavior is

"find dco:Project where community is dco:Community1 or dco:Community2 and group is dco:Group1"

instead of

"find dco:Project where community is dco:Community1 or dco:Community2 or group is dco:Group1"

Fixes #5