Need a service to turn a list of study ids into a list of DOI + bibliographic information blobs

[jar398]

The tree_of_life tree-returning methods now return a supporting_studies list (see OpenTreeOfLife/treemachine#223), but for that to be useable for applications the bibliographic information will need to be obtained. To make this as easy as possible for clients, I'm proposing an OTI service that would be directly applied to the supporting_studies list pulled from the tree_of_life service result.