Sped up hierarchy widget paging on large sets.

I noticed when working with a large collection (>100000 items), that the hierarchy widget was very slow to load a page of data.  Internally, mongo was using the folderId index, but not the name index.  By adding an index that uses both of these fields, mongo is more sensible and pages the data quickly.
Merge pull request #462 from girder/improve-mongo-indices-for-hierarchy

Sped up hierarchy widget paging on large sets.
Fixes #447. Jquery npm version was breaking on newer npm
Shot in the dark -- remove cffi explicit dependency
Revert "Shot in the dark -- remove cffi explicit dependency"

This reverts commit 4cfe3d5bcc06ab6004401cd7cd0f88732ddb6586.
Attempt to fix travis bcrypt issue.
Merge pull request #466 from girder/npm-install-error

Fixes #447. Jquery npm version was breaking on newer npm
Merge branch 'master' into provenance_plugin