Mainline fixes + Silence React 15.2 prop warnings

See: https://github.com/christianalfoni/formsy-react/releases/tag/v0.18.1

React 15 + Mainline fixes

This release pulls in the changes from mainline v0.18.0.

Most notably you can use React 15 as a peerDependency.

defaultValue

Adds support for defaultValue on Formsy inputs.

Add skipFormRender

You can set call Formsy as: <Formsy.Form skipFormRender> and that will not render a <form> tag in the DOM. This is useful when one wants to nest Formsy in an existing form or nest Formsy inside another Formsy.

v0.8.0

• Fixed bug where dynamic form elements gave "not mounted" error (Thanks @sdemjanenko)
• React is now a peer dependency (Thanks @snario)
• Dynamically updated values should now work with initial "undefined" value (Thanks @sdemjanenko)
• Validations are now dynamic. Change the prop and existing values are re-validated (thanks @bryannaegele)
• You can now set a "disabled" prop on the form and check "isFormDisabled()" in form elements
• Refactored some code and written a couple of tests

v0.7.1

• Fixed bug where external update of value on pristine form element did not update the form model (Thanks @sdemjanenko)
• Fixed bug where children are null/undefined (Thanks @sdemjanenko)

v0.7.0

• Dynamic form elements. Add them at any point and they will be registered with the form
• onChange() handler is called whenever an form element has changed its value or a new form element is added to the form
• isNumeric validator now also handles actual numbers, not only strings
• Some more tests

v0.6.0

• onSubmit() now has the same signature regardless of passing url attribute or not
• isPristine() is a new method to handle "touched" form elements (thanks @FoxxMD)
• Mapping attributes to pass a function that maps input values to new structure. The new structure is either passed to onSubmit and/or to the server when using a url attribute (thanks for feedback @MattAitchison)
• Added default "equalsField" validation rule
• Lots of tests!

v0.5.2

• Fixed bug with handlers in ajax requests (Thanks @smokku)

v0.5.1

• Fixed bug with empty validations