Allow to have many translator instances and behave similar as Bing and google translator does

Gems for google translator
(https://github.com/seejohnrun/easy_translate) and Bing translator
(https://github.com/relrod/bing_translator-gem) uses same method name
#translate and accepts same attributes for translating text. In this
case we can use duck typing
Version bump to 0.3.0
Merge pull request #6 from bloomrain/duck-typing-improvement

Allow to have many translator instances and behave similar as Bing and Google translator does