Workaround for intermittent HSQLDB start failure

When running the build there is an occasional HSQLDB startup failure.
The root cause for this failure is:

  java.net.SocketException: Invalid argument

This exception is thrown on JDK 7 OS X when there are > 1024
open file descriptors. See this Stack Overflow thread:

http://stackoverflow.com/questions/16191236/tomcat-startup-fails-due-to-java-net-socketexception-invalid-argument-on-mac-o

This is fixed in Java 7u60:

https://bugs.openjdk.java.net/browse/JDK-8021820

In the meantime, this workaround will trap that exception and
make several attempts at starting up HSQLDB before giving up.

Previously it was assumed that a startup failure was due to
a port conflict. This is unlikely because an open port is
selected by the test prior to configuring HSQLDB. If this does
happen the log file will indicate so:

org.springframework.beans.factory.BeanCreationException:
  Error creating bean with name 'hsqldb' defined in class...
...
Caused by: java.lang.IllegalStateException: HSQLDB could not be started on 0.0.0.0:6379, state: SHUTDOWN
...
Caused by: java.net.BindException: Address already in use
	at java.net.PlainSocketImpl.socketBind(Native Method)
	at java.net.AbstractPlainSocketImpl.bind(AbstractPlainSocketImpl.java:376)
...

Rework of the while loop

Modified the while loop to use a boolean instead of
always forcing a break. A server start failure
still causes a break. This avoids the need for
another boolean to track whether an error occurred.
Merge branch 'master' into zk-runtime
Added command line option to generate heap dumps

If a test generates an OutOfMemoryError, a heap
dump will be generated that can be used to determine
the root cause.

See http://docs.oracle.com/javase/7/docs/webnotes/tsg/TSG-VM/html/clopts.html
Merge branch 'master' into zk-runtime
Fixed compile warnings
Improved stream-command-tests
Misc cleanup, Javadoc, refactoring

Removed PathChildrenCache for jobs and streams as members
of AdminServer and placed them as local variables in
takeLeadership since they are only used in that method.

Added JavaDoc to AdminServer.

Minor formatting.