Changeset 10130 for trunk/sources

#2117

• fixed drag and drop check in the RefreshableHiveJobView to be more generic
• fixed TaskDownloader to generate the correct HiveTasks when downloading tasks
• fixed some variable names (job => task) which were forgotten
• the IsParallelizable property of a task can now be set (e.g. if a task gets parallelized, the generated child tasks should sometimes not be able to get further parallelized)