AIA-25 - Application posts issue changes which were already posted before
Added testThatAfterIssueCreationIsPostedItIsNotPostedAgain which tests that when a new issue (issue which was not reported in the RSS before) is posted to the chat server, then after it's detected in the feed next time with no changes (for example comment has been added), it is not posted as created issue to Slack again
Added testThatIssueWithNoChangesWhichWasNotReportedBeforeCausesPostingOfIssueCreation which tests that when a new issue (issue which was not reported in the RSS before) is posted to the chat server as a new issue, e.g. {@link com.ontometrics.integrations.configuration.ChatServer#postIssueCreation(com.ontometrics.integrations.events.Issue)} is called
Merge remote-tracking branch 'origin/master'