Replaced icon as the previous base class will be removed in future versions of the MSL.
Replaced icon as the previous base class will be removed in future versions of the MSL.
Corrected latent heat gain for humidifier, improved documentation and instance names.

This is for #197.
Merge pull request #198 from lbl-srg/issue197_humidifier

Corrected latent heat gain for humidifier, improved documentation and in...
Improved error message.
Merge branch 'master' into issue196_borehole