rerun a group requesting different resources

[mariux]

rerun (failed) jobs of a group requesting different resources

• more memory
• more time
• more threads

issues:

• reconnect/move finished jobs to new group?
• only restart failed/unknown/cancelled jobs?
• combine both groups in stats?
• running groups shall not be rerun. only cancelled or finished groups (group_date_end > 0)

this is related to #15 because we can't depend on failed groups.

[mariux]

close group when rerunning see issue #24

[mariux]

running groups shall not be rerun. only cancelled or finished groups (group_date_end > 0)