Warn about unknown property values

Fixes #255.
Fix controlled radio button behavior

Fixes #242.
Merge pull request #267 from spicyj/warn-props

Warn about unknown property values
Merge pull request #281 from spicyj/radio

Fix controlled radio button behavior
Move else if (__DEV__) into two statements

The minification stage doesn't like `else if (__DEV__)`.
Merge pull request #325 from spicyj/elseifdev

Move else if (__DEV__) into two statements