Add a spec for Module#public when given an undefined name

`raise_error(NameError)` matches NoMethodError too.
Add a spec for Module#protected when given an undefined name
Add a spec for Module#private when given an undefined name
Add a spec for main.public when given an undefined name
Add a spec for main.private when given an undefined name
Fix specs for Module#public_class_method when given an undefined name
Fix specs for Module#private_class_method when given an undefined name
Fix exceptions when visibility setters given an undefined name

* Module#{public,protected,private}
* Module#{public,private}_class_method
* main.{public,private}
Merge remote-tracking branch 'kachick/adjust_exception_from_setting_visibility'
Removed implementation dependent example for equal matcher.

MRI 2.0 treats Floats as immediates if double-tagging is used.
Removed Gemfile.lock for mspec.

In RSpec, raise_error and raise_exception are aliases. Since "error"
is a more general term, it's reasonable that it matches "kinds of"
exceptions. Here, raise_exception is used to match only a specific
kind of exception. Any confusion that results will be short-lived
as MSpec 2.0 will use a different syntax.
Added raise_exception to MSpec.
Switched to raise_exception for some NameError specs.
Merge branch 'master' of github.com:rubinius/rubinius