Merge pull request #1 from mono0x/master

Fix typo.
Version bump to 0.1.2.
Regenerate gemspec for version 0.1.2.
Change gem builder to bundler from jeweler.
Delete dependency to rubytter.
Backport to 1.8.
rm Gemfile.lock.
Change initializer arguments.
raise ArgumentError when that not block given.
Add spec that change how to use library.
Change how to use library.
Split client class with api class.
Change to UserStream module from Userstream class.
Add user_stream alias to userstream.
Rewrite README.
Version bump to 1.0.0.
Fix configuration file name.
Add document.
Sort options keys.
Change to private method.