port method handling code from mocks so we can use original definition of method
handle finding method handles for basic object
restore fallback to method
note still won't work for `BasicObject`, that doesn't include `Kernel`
or an object that is based on `BasicObject`, includes `Kernel` but
redefines `method`.
on ruby 2.0.0 cut straight to `Kernel.method`
prevent `BasicObject` specs from running on 1.8
Merge pull request #315 from rspec/port_mocks_method_handle

Refactor finding method handles