define_singleton_method should be in Kernel
Untagged passing specs

Kernel#define_singleton_method
- defines a new method with the given name and the given block as body in self
- raises a TypeError when the given method is no Method/Proc
- defines a new singleton method for objects
- maintains the Proc's scope
Tagged failing specs

Kernel#define_singleton_method when given an UnboundMethod
- will raise when attempting to define an object's singleton method from another object's singleton method
Merge branch 'master' into kernel_define_singleton_method

Conflicts:
	spec/tags/core/kernel/define_singleton_method_tags.txt
Merge pull request #729 from krekoten/kernel_define_singleton_method

Kernel#define_singleton_method