refactored nexson_syntax tests into separate files for low-level conversion and use of the PhyloSchema class
new test reveals bug in unused functionality
bug fix in generating a phylesystem_url. Code not used.
several more test. and making the URL shorter when the default NexSON is requested
Merge pull request #73 from OpenTreeOfLife/cull-non-matching-trees
Merge pull request #75 from OpenTreeOfLife/papers

Papers
minor edits from karen
Merge pull request #76 from OpenTreeOfLife/karen-manuscript-edits

minor edits from karen. You are correct about the sorting of entries...
As to the [KAC] comment...well... I'm afraid we use 3 syntax variants of nexson for historical reasons.  
we're not that old, but we have legacy and backward compatibility issues already...
merge of KAC's contributions with some of my typo corrections