array#select!, keep_if
Implement String#casecmp
Tag a bunch of new tests
started implementing Kernel#__method__
Module.nesting and Module#remove_class_variable
added flags on modules
strings can be symbols (sometimes?)
Make flags and duping work on Modules
error condition on Module#module_eval
Stub out Module#private_constant
tag a bazillion specs that now run
Skip another test.
Merge pull request #623 from kachick/implement-string-casecmp

Implement String#casecmp
Merge pull request #569 from kostya/select_i

array#select!, keep_if
Implement String#start_with?
Implement String#end_with?