Fix a HA failover bug where the master tries to become a master again and fails.

Instead of failing just log a warning, turns out this case can happen in a real-world scenario where the storage delays the writes of the master.
Stop strayed JMX feed
Adds working-directory tips to ide.md, and relevant sections of the code to help resolve 'gui not available' issue
This closes #251
This closes #250
This closes #245
tidy up of logging for persistence and location management
cleans up some of the mess in LocationRegistry around testing-vs-resolving and managed-vs-unmanaged, deprecating many methods (and removing their calls)
fix a few failing tests (nothing major) and optimize a bunch more
minor tidies of location leaks, for code review
This closes #233
exclude maven check-style in eclipse, to suppress eclipse errors
support changing mode to disabled, ensuring things really are purged from memory; and allow HA tests based on RebindTestUtils/Fixture
better bookkeeping for scheduled tasks (counts go to 0 now), and set tags on scheduled tasks
switch incomplete tasks to be tracked by ID, rather than a simple count, so we can GC those which are interrupted (and so their afterEnd method is never called),
ensuring incomplete counts are accurate modulo interrupted-but-not-garbage-collected tasks; and log if tasks are removed while active
ensure feeds (and all entity tasks) are cancelled when entities are unmanaged, including in-memory test and an integration test with nginx; now it will GC entity tasks *after* fully unmanaged, but will cancel entity tasks *during* unmanage. also fixes nginx issue where it tries to reload conf immediately on rebind
a few minor tidies for GC'ing tasks and alerting on nginx reload/update failure
tidies after code reviwe for stopping tasks on unmanagement, and option for stopping tasks with timeout and investigation of errors occurring on rapid entity destroying just to make sure they are benign and handled well (and they are :) )