Add Hash#delete_if
simply use `isfinite`
Fix comment of exc_inspect (and adjust spaces)
Merge pull request #2181 from suzukaze/add-hash_delete_if

Add Hash#delete_if
Merge pull request #2182 from cremno/use-isfinite

simply use `isfinite`
Merge pull request #2183 from yui-knk/fix-error-comment

Fix comment of exc_inspect (and adjust spaces)