service_process_is_running absence will not trump service_up even on rebind

modify service_process_is_running enricher to be better about respecting entities which manually set service_up;
previously it did not change service_up *except* on a rebind; now it should not even change them on a rebind

also switch mysql to support service_process_is_running
jmx agent path is set as a sensor to work across versions

also deprecate a needless inner class (but keep it around for rebinding)
fix bug *listing* in object store when container name is a virtual path

previously if container name contained a /, when listing, all items included container name portions after the initial /.
better test coverage now too.
This closes #348
This closes #344
add comment for code review
This closes #347
tidy think-we-are-master-when-we-are-not discrepancies

fix test which depended on promotion when master-becomes-master-again, and
when considering demotion look at whether we were master *locally* not globally,
on reassertion, rewrite the master file and the change.log;
and throw if we fail going in to hot backup
force catalog to load on access of getCatalogItems()

some callers use that to force catalog load, so support that behaviour. in time maybe we can throw this away or simplify it hugely.
log number of threads as part of GC info
make BrooklynClassLoadingContext instances serializable

clean up how we set and manage those; fix bug where serialized state of `/Users/alex/Data/cloudsoft/dev/gits/brooklyn/docs/use/guide/defining-applications/example_yaml/appserver-clustered-w-db.yaml` was 8 MB !  also rename methods and internal fields to make things more standardized, and dampen down some logging
fix hot proxying seeing old entities (below the app level)

fix bug where newer real entities preRegistered were not being picked up, in favour of older instances, so new data was not being seen at children at hot_proxies
misc tomcat blueprint fix
clean up logic for HA start+change mode
allow explicit setting master

this is in fact needed, as otherwise if a previous master has failed we have no way to force a new master sooner than the heartbeat timeout
more HA change mode fixes