Added update fixed versions support.

Added two new paramters in the configuration: resettingFixedVersions (boolean) and fixedVersionNames (String consists of multiple version names delimited with comma). 
The new feature tries to overwrite/add (resettingFixedVersions: true/false) the secified versions to the issues found by the jql search. Since the jira version is project specific, the versions not applicable to an issue were ignored (error messsages are logged).