Basic functionality for importing and exporting models to/from public library
Implemented the following suite of features with regards to model sharing:
  1) Users now have the ability to name a model before exporting to the public library
    a) Duplicate names are not allowed
  2) Exporting no longer redirects the user to a different page
  2) Users now have the ability to preview a model in the public library (as XML) before importing
  3) Users now have the ability to delete a model from the public library
Minor bug fixes related to previews of custom models and ordering of models in Public Library
Merge branch 'model-sharing' into sensitivity