Smarter edge styles, restored edge studies info.

We now distinguish between edges that are supported by taxonomy, phylogeny, or both. Also restoring study info (incl. full references) for edges that have them, even if they don't have a DOI in the reference.
Grouping and sorting of child nodes in argus

These display changes will support further clustering of less-interesting edges (supported only by taxonomy).
Generating clusters for less-interesting nodes.

These will appear if we exceed some reasonable (legible, fast-loading)
number of child nodes, for example on 'Metazoa'.

NOTE that this doesn't yet load the clustered children incrementally.
Working "clustering" behavior in populous clades.

This is not elegant code, but it shows the desired behavior. If we don't opt to move from RaphaelJS to d3 (or similar), we should refactor this to establish stateful subtrees and ongoing links between data, display state, and the visible SVG/VML elements.
Merge pull request #54 from OpenTreeOfLife/argus-performance

Argus performance (using "clustering" in populous nodes)