Introduce argument check logics

[tagomoris]

Currently method argument checks are not common between CRuby and JRuby. It's better to have common argument check for better compatibility (ex: io-like object of Buffer#new arguments) and throw ArgumentError for invalid values.

But it could break working application code (w/ ignored or danger argument values). So this change should be done as major or minor version up, not patch version bump.

[chrisseaton]

Have you got an examples of incompatibilities?

If not I think I'm likely to close this pretty old issue.