Javadoc
don't let stringify convert `null` to `"null"`
compute UPTIME sensor
fix bug where nginx up-detection continued to run after service stoppage
remove the hand from sensor/config values, as they aren't clickable
use generics for RendererHint, simplify class hierarchy there, and add support for rendering based on class type, used for Duration and HostAndPort, and for Entity instances to show the name of the entity
BROOKLYN-71: DelegateSecurityProvider listens to property changes

Reloads the provider when notified and forces existing sessions to
reauthenticate.
fix intermittent deleting-dir test failure by waiting for server shutdown before deleting dir
better logging and tighter assertions to debug jenkins-failing ServiceReplacerTest, and extracted unit test isolating the problem
set service up before expected running in TestEntity to correct test failures
useful logging if setting expected RUNNING when service is not set up
set transitioning fields on cluster when resizing to or from 0, and better comments on failures
add repeat-untils for some brooklyn-GC-related tests (maybe there is a 1ms window between tasks finishing and that fact propagating thus the tasks being cleanable...)
better log for service state logic
back out logic where DynamicCluster tried to be smart about setting transitions starting/stopping when resizing from/to size 0;
now it does not. 0 is not a valid size for a running cluster. makes sense as a default. notes for how to do something different here.
also minor tidies to ServerPool which was sensitive to this behaviour.
Split rest request filter logic up

* Rest API logging much more limited: GET/HEAD logged at trace, others
  and errors at debug.
* Adds brooklyn.rest.filter package.
This closes #208
fix NPE in SensorResource
fix for loss of stdout/stderr streams
This closes #213