Recent opentree changes for Cavia

@kcranston , @jar398 : This includes some significant improvements, esp. for resources in **files.opentreeoflife.org**. Note that this also includes the current `devtree` UI for choosing among OTU mapping options, which we plan to revise as described here:
	https://github.com/OpenTreeOfLife/opentree/issues/407#issuecomment-53448080

I can revert just the commits for this UI, but that will leave us unable to choose among mapping options where more than one are available.