Basic implementation of 'Nestings' and 'NestedObjectProperty'.
Continued implementation of nestings:
* builders are now separated by the inner observable
* implemented shallow nesting
* defined types for nested properties
* defined behavior for nested properties when inner observable is null
* improved tests for nested properties
Wrote tests for nestings.
Tests now assert that nested properties correctly update their 'observableNull' property.
'Nesting.innerObservable' now contains an 'Optional' of the nested observable to make clear that is might be null.
Improved tests for nested properties and wrote tests for property builders.
Added a simple demo for nested properties.
Readme now explains what happens in the branch.
Small changes to README.
Renamed project to LibFX.
Updated README to new project name.
Minor, non-functional changes.
'NestedProperty' now implements 'ReadOnlyNestedProperty'.
Fixed tests, so their value comparison does not rely on interning.
Fixed some comments.
Implemented 'NestedDoubleProperty' including the builder and tests.
Property nesting builders now return the most specific types of properties, namely those which extend 'Simple...Property' and implement 'NestedProperty'.
Implemented 'NestedFloatProperty' including the builder and tests.
Fixed some comments.
Minor harmonization of some tests.