Fixed broken URL links (#119)

* Fixed broken URL links

Incorrect reStructuredText was breaking most of the URLs preventing someone from clicking on the link (characters %3E%60 were added to the hyperlink).

* Update README.rst

Remove space from the first line, and reversed my changed in the reStructured text formatting per comments thread.

* Update README.rst

Added required underscores following the backquotes for URL formatting.

Author: mhaddy

ask-sdk-core/README.rst

@@ -1,4 +1,4 @@
- ====================================================
+====================================================
 ASK SDK Core - Base components of Python ASK SDK
 ====================================================
 
@@ -48,5 +48,5 @@ Got Feedback?
 
 - We would like to hear about your bugs, feature requests, questions or quick feedback.
   Please search for the `existing issues <https://github.com/alexa/alexa-skills-kit-sdk-for-python/issues>`_ before opening a new one. It would also be helpful
-  if you follow the templates for issue and pull request creation. Please follow the `contributing guidelines <https://github.com/alexa/alexa-skills-kit-sdk-for-python/blob/master/CONTRIBUTING.md>`_!!
+  if you follow the templates for issue and pull request creation. Please follow the `contributing guidelines <https://github.com/alexa/alexa-skills-kit-sdk-for-python/blob/master/CONTRIBUTING.md>`_!
 - Request and vote for `Alexa features <https://alexa.uservoice.com/forums/906892-alexa-skills-developer-voice-and-vote>`_!