Remove static methods from the interface.
Remove static methods from the interface.

Given that interfaces are most frequently used to typehint arguments, or
check instances types, static methods don't really make sense in an
interface. Static methods should not be called on instances.

Many other languages with interfaces don't even allow static methods on
interfaces (java<8, c#). Most of the static methods we had were factory
methods, which also don't necessitate an interface.

antograssiot/chronos,cakephp/chronos,bcrowe/chronos