Remove unused imports, variables, and semicolons

Also some whitespace adjustments for better consistency.
Remove unused subdirectory "spool/scripts"
Fix bug with usage of cmd_restart_pre method

The cmd_restart_pre method was being called without the last argument.
The example plugin "TestPlugin" was also incorrect.
Minor fixes for broctl tests

Fixed issues in broctl tests caused by recent changes in bro and broctl.
Need to set BROMAGIC in broctl-test-setup script for debugging tests,
and "broctl status" command now returns non-zero when nodes are not running.
Documentation fixes

Fixed a broken link.  Added information about how to disable the
connection summary reports.
Merge remote-tracking branch 'origin/master' into topic/dnthayer/cleanup4
Merge remote-tracking branch 'origin/topic/dnthayer/cleanup4'

Yeah, all BroControl tests pass for me now!

BIT-1061 #merged.

* origin/topic/dnthayer/cleanup4:
  Documentation fixes
  Minor fixes for broctl tests
  Fix bug with usage of cmd_restart_pre method
  Remove unused subdirectory "spool/scripts"
  Remove unused imports, variables, and semicolons