newick and nexus export of trees
typo in var name fixed
GET .../study/ID/tree/ID syntax
file extension in content negotiation

Using the PhyloSchema format specifier in peyotl to make it
easier to extend.
getting the file extension for output sniffing request.extension
merged manually
not passing content_id for study
subtree and otu-related slicing of studies
ignoring .json suffix
documenting new fine-grained access via GET
Merge branch 'master' into treesource
indentation
Merge branch 'master' of github.com:OpenTreeOfLife/phylesystem-api into treesource
Merge pull request #92 from OpenTreeOfLife/treesource

Treesource