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