4.1.0

• Add assign function to assign properties values using any object, silently ignoring fields which are not properties.
• Add from function to initialize a model and assign properties values using any object, silently ignoring fields which are not properties.
• Add applyPatch function to update models using objects returned by patch function.
• Add map type and document it.
• Add extend function to easily extend an inherited model.

• Change recommended model declaration.
• Improve code and tests style.
• Update dev dependencies.
• Improve README.