Add Coverage badget

Author: pitbulk

README.md

@@ -1,5 +1,7 @@
 # OneLogin's SAML Java Toolkit
 
+[![Coverage Status](https://coveralls.io/repos/github/onelogin/java-saml/badge.svg?branch=v2.0.0)](https://coveralls.io/github/onelogin/java-saml?branch=v2.0.0)
+
 Version 2.0.0
 
 Not ready yet, it lacks documentation and not officially distributed.
@@ -41,4 +43,4 @@ Known issues while testing:
  * When using @PrepareForTest and PowerMockito the breakpoints not does [not stop when debugging](http://stackoverflow.com/questions/35140575/powermockito-junit-and-eclemma-debugging-dosent-work). The solution is define Rules.
 
  * Java7+ enforces bytecode verification and with Powermock you can experience a [java.lang.VerifyError](http://www.notonlyanecmplace.com/java-7-enforces-bytecode-verification/).
-   At Java8 bytecode verification is mandatory and there is no option to disable it :(
+   At Java8 bytecode verification is mandatory and there is no option to disable it :(