v4.0.4

Fix to handling of turf modules import for GeoModel.js. Recent changes to Babel broke the earlier version of the code.

v4.0.1

Change include:

• Addition of BaseModel#findOrCreate() method.
• Minor hange to BaseModel#extend() method signature (removed an optional second parameter which appears to never have been used).
• Removal of superfluous files from npm package.
• Updates to documentation.