Azkaban Plugins 3.0.0: Cancel method for jobtypes, azkaban job props via reportal variables and spark jobtype updates.

Update build versions to support java 1.8 , add logic to correct the mail content type in reportal. #208
adding the cancel method for Hive, HadoopJava, Pig #201
Allowing users to specify global job properties using reportal variables #203
updates to spark job type #205
adding execute-as-user parameters as default setting #209

Please refer to latest documentation for details.