Make use of immutable library.
Add immutable to deps
validate: do not deserialize null
Value: remove unused method
Makefile: better test runner
Update integration tests
Value: keep track of dirtiness.
Field: add test case for onBlur
Field: better assertions after onChange
Perf optimizations.

Added shouldComponentUpdate to <FormElement /> and <Label />, do not transfer
value prop to DOM elements (<div />).
Remove incorrect optimization
Remove incorrect optimization
docs: start fixing examples
<FormElement /> => <Element />
<FormInput /> => <Input />
Gardening
Add immutable to dev deps
Fix Value.concat behaviour
Gardening
Gardening