Fix #1106 - plugins using ssl throwing exceptions
<yawkat> is that debug code i spot md_5?
Block all of java, not just java.lang
Add basis of grouped thread factory and make the scheduler use it.
Override context specific permission check
Revert "Delay kicks in initial handler."

This reverts commit 7347daf20302ed426816c52485a9468c9e94af7f.
Remove security manager