Issues for testing Pymt demo Jupyter Notebooks

[gantian127]

I tried to test all the Pymt example Jupyter Notebooks (https://github.com/csdms/pymt/tree/master/docs/demos) on HydroShare Jupyterhub and had the following issues. Thanks!

• subside:
  issue 1: import "plugin" error
  

• Sedflux3D:
  issue 1: import "plugin" error
  issue 2: no "get_current_time", "get_time_step" attribute (But most of the other cells seem to work well)
  

• child:
  issue 1: import "plugin" error
  issue 2: no "child" model
  

• Sedflux3D_and_child:
  issue 1: import "plugin" error
  issue 2: no "child" model

• Example_01_Basic_User_GIPL/ Example_02_GIPL_ECSimpleSnow: (may not be an issue)
  A user needs to run the following command in the HydroShare Jupyterhub terminal before running the code:
  conda install pymt_gipl pymt_ecsimplesnow seaborn -c conda-forge

[mdpiper]

Closed with csdms/pymt#94. Thanks, @gantian127!