Merge topic 'export-import-smtk-model'
53d5dabb Fix linux build error with ifstream constructor 60be0d69 Add all new non-sub models to created after ImportSMTKModel op 048a0acf Dont overwrite url for existing model while importing smtk model 99e021d6 Refactor some logic in json import and export of models and meshes. 8ec9713b Modified some tags in session exporting and importing 8ff0325e Made discrete write-op to be like write-ops in other sessions 80683af9 Adding methods and operators for saving session models and meshes f164badc More methods for writing JSON meshes and collections Acked-by:Kitware Robot <kwrobot@kitware.com> Merge-request: !24