Re-use ssh connection

- Previously only re-using if no flags were supplied; now re-use also
  if it's just that stdout/stderr have custom capturing.
  Important for SshSensorAdapter.
issue 452 fixed JcloudsLocation override of groupId causes DnsNameValidator to fail in jclouds
"brooklyn-fullusername-uids" on those clouds which don't have short limits, added unit test
Add `MySqlNode.DATA_DIR` config key for specifying the location of the DB files
Specify correct --datadir option.
Test override of MySQL data location in integration test.
Merge pull request #443 from aledsage/fix/reuse-ssh-connection

Re-use ssh connection
Merge pull request #432 from alasdairhodge/mysql-data-location-config

Permit configuration of MySQL data directory
#463 proposal for deadlock fix
peter's comments addressed
alasdair's comments addressed
Merge pull request #464 from andreaturli/deadlock

#463 proposal for deadlock fix
fixed import
Fixes EntityExecutionManagerTest of GC

- change toString so not logging 10MBs of zeros in effector params
  and in sensor setting.
Merge pull request #465 from aledsage/fix/EntityExecutionManagerTest

Fixes EntityExecutionManagerTest of GC
Merge pull request #454 from digitalsanctum/issue-452

fixed JcloudsLocation override of groupId causes DnsNameValidator to fail in jclouds
Adds javadoc for feeds
fix hello-world.war for jboss6

- use separate servlet-mapping elements for each url-pattern;
  previously had been changed for testing url-mappings to have:
    <servlet-mapping>
        <servlet-name>HelloServlet</servlet-name>
        <url-pattern>/hello</url-pattern>
        <url-pattern>/hello/*</url-pattern>
        <url-pattern>/goodbye/*</url-pattern>
    </servlet-mapping>
Fix TomcatServerIntegrationTest
Fix ControlledDynamicWebAppCluster rebind test

- The DeferredSupplier anonymous inner class used in the cluster's
  config was not serializable