array#select!, keep_if
Fix Comparable#== for weird values
Merge pull request #621 from kachick/fix-comparable-equal_value

Fix Comparable#==
Hash#element reference call eql? on objects in right order
fix some rubyspec master tags
Merge pull request #625 from kostya/fix_tags

fix rubyspec master tags
Merge pull request #624 from kostya/eql_in_hash

Hash#element reference call eql? on objects in right order
Expose ivars and cvars on classes.
these pass
remove a duplicated line
array#product
fixes
fixes
Implement Numeric#abs2

`self ** 2` is failed on RubySpec.
Because calling Numeric#* is a spec.
Merge pull request #629 from kachick/implement-numeric-abs2

Implement Numeric#abs2
Fix Array#[]= for frozen objects
Merge pull request #630 from kachick/fix-array-subscript_assign

Fix Array#[]= for frozen objects
Implement String#casecmp
Tag a bunch of new tests
started implementing Kernel#__method__