opal/opal — pull request #524 by mieko (2014-03-27 14:57:43+00:00)
Title: Hash fixes: low-hanging fruit.

* `Hash#delete` accepts a block for default value
* `Hash#default` and `Hash#default_proc` unset their counterpart.
* `Hash#merge`/`Hash#update` try to coerce with `:to_hash`
* `Hash#==` Checks for value existence in rhs before comparing
* `Hash.new` throws proper errors for more malformed argument list "geometries".

Also closes #522 (value existence on rhs)