Created a new README.md file as contents from README.html were out of date
fail when AssertionError expected but not thrown

When a user expected the production code to throw an AssertionError by
using ExpectedException (together with the #handleAssertionErrors
option) but the code under test didn't do so the test was not failing.
This was because the ExpectedException rule caught its own
AssertionError issued to signal that the expected exception was not
thrown.
assertion on complete error message
Fixed formating in Enclosed Javadoc
correct formatting
Merge pull request #581 from shirish4you/master

Create README.md
Fixed typo [WiKi -> Wiki]
Merge pull request #590 from shirish4you/patch-1

Fix typo [WiKi -> Wiki]
Removed references to README.html

Removed references to README.html and replaced with README.md
Merge pull request #591 from shirish4you/patch-2

Package README.md instead of README.html in ZIP file
Added build status to readme

https://junit.ci.cloudbees.com/job/JUnit/badge/icon gives latest build status icon
Merge pull request #583 from UrsMetz/expected-exception-fail-when-assertion-error-expected-but-not-thown

ExpectedException doesn't fail when an AssertionError is expected but not thrown
Added link to Jenkins instance for build status
Merge pull request #586 from Tibor17/junit.fix

Fixed formating in Enclosed Javadoc
Merge pull request #594 from shirish4you/patch-2

Added build status to readme