Documentation updates including column/field names for GeoJSON and Shapefiles

[kaklise]

Summary

The following PR includes documentation edits and a function that returns valid base column/field names for GeoJSON and Shapefiles which is used to document file format. Each element type (Junction, Tank, etc) now includes a _base_attributes and _optional_attributes list. The _base_attribute are used in methods like add_junction while the additional optional attributes are also used to build a water network model from the dictionary representation in from_dict.

Bug fixes:

• Added min_vol to tanks in from_dict
• Fixed valve connectivity warning message

Tests and documentation

• Documentation updates

Acknowledgement

By contributing to this software project, I acknowledge that I have reviewed the software quality assurance guidelines and that my contributions are submitted under the Revised BSD License.

[coveralls]

coverage: 84.428% (+0.08%) from 84.353% when pulling 54120e1 on kaklise:docs into 423e8cd on USEPA:main.

[dbhart]

All these changes look appropriate and in line with review comments from sponsors