updated protocol version to tls

this will solve the issues with server not responding to sslv3 due to bug found in the protocol (POODLE)
fixed unit tests
added testing of ruby 2.1.3 on trevis ci
updated documentation
added ruby 2.1.3 in the ci rubies to test the project on
fixed ca_file integration test
fixed the last integration test

thanks to @pcorliss
on
https://github.com/rest-client/rest-client/commit/d242580dd57d5abe34e890
c6efe1e88c1a96bbc4 commit, because I couldn’t figure it out how to
provide the certificate files to make the tests pass
Merge pull request #5 from formigarafa/fix_failing_tests

Fix failing tests
Merge pull request #3 from formigarafa/patch-1

updated protocol version to tls
Merge pull request #1 from treeder/master

catch up with origin repo. I know it is failing. but I am merging to find a fix for it