Flush Graphite on close

When a large number of metrics needs to be reported, flushing
Graphite.writer in each call to send() greatly limits metric
reporting throughput.
Add Graphite UDP sender
create metrics-httpasyncclient module
instrument the NClientConnManager
Instrument the HttpAsyncClient using the builder
test
-
add module to parent pom definition
Update JmxReporter.java

Lazy fetch of mBeanServer, only call ManagementFactory.getPlatformMBeanServer() when none is set in the builder pattern
Merge pull request #578 from tvleminckx/master

#577 Lazy fetch of PlatformMBeanServer
ElementType.TYPE annotation support, closes #571
Suppress runtime exceptions thrown from ScheduledReporter#report
Travis-CI: Enable JDK8
java 8 doclint: allow <p/> in javadocs by disabling strict HTML4.0 compliance

* by default java 8 doclint consider <p/> tags as errors
  https://bugs.openjdk.java.net/browse/JDK-8020619
java 8: disable findbugs as findbugs-maven-plugin doesn't yet support jdk8

* current findbugs-maven-plugin 2.5.4 is based on findbugs 2.0.3,
  while JDK8 is supported starting findbugs 2.1.0
java 8 doclint: resolve errors and warnings for missed table caption, @return and @param
Merge pull request #584 from ceetav/metrics-jdk8

Enanle Travis-CI JDK8
migrate Metrics to Jersey2, include a module for Jersey1 as well to allow people still using Jersey1 to keep using it
upgrade pom to latest parent version number
remove bad Javadoc comment left over from the previous Jersey module