[FIX] Duplicates from search

[abourn]

• Check if the release group id exists in results before adding
• But, how do we handle cases in which certain releases within a release-group actually have more or less tracks...? For example, M.I.A.

[abourn]

This may turn into a more general search enhancement for v2. For example, we want to have duplicates when a release is being indexed on a different field (e.g. track title is the same as track release). In trying to resolve this, checking if the current node has that specific release and that specific index info before adding to the trie (nodeContainsRelease() of trie.go; check would be val.ReleaseID == releaseID && val.FieldMatchedOn == fieldToIndex) seems to break other behavior (i.e., not indexing as much as it should).