Cleanup of error handling in AbstractOutputWriter. If an error is detected in any of the threads then record the error so that subsequent calls of writeLine(String, Bundle) will propagate the error to exit the job. Converted the fields 'stopped' and 'exiting' from AtomicBooleans to volatiles because no test-and-set operations are performed on these variables.
Merge pull request #20 from mspiegel/output-writer-error-handling

Cleanup of error handling in AbstractOutputWriter.
Abstracting most of the functionality of DataOutputFile
into a parent class so that the implementation can be used
by other classes.
add ability to reference columns by name in bundle calculator
fix aliasing to a node that does not yet contain children
Merge pull request #21 from stewartoallen/at-pull-001

add ability to reference columns by name in bundle calculator
Adding javadoc annotation for 'fold' query operation.
Merge pull request #22 from stewartoallen/at-pull-002

fix aliasing to a node that does not yet contain children
add support for array returns in element query
[cherry pick commit from stewartoallen a0549909393c8e3206c30becd2bf357adbb97b77]
Promoting VirtualTreeNode class visibility to public.
Cherry pick of stewartoallen 1fdaa14156f33ab9159ca4da1fc670e151169596.
Renaming static inner class from "ITER" to VirtualTreeNodeIterator.
{{LAST}} is not a valid parameter
Update signature of DataOutputFile#setWriter() to return the concrete type
instead of the abstract base class.
[maven-release-plugin]prepare release v4.1.3
[maven-release-plugin]prepare for next development iteration
Bugfix for reverse polish notation calculator. "=" cannot be used for integer equality
it is already used for assignment. Update Javadoc documentation to include "eq" operation.
formats get corrupted if we re-use the input bundle for map processing, modified to copy the bundle.  sucks that we have to do this...
Initial commit of recognition when the parent directory of a task
has been deleted.
improve documentation for QEC section
clean ups for QE(C)

- reduce a couple log message conditions
- use Iterators.emptyIterator() instead of a static empty list
- some fields become final
Merge pull request #28 from mspiegel/task-no-parent-dir

Recognition when the parent directory of a task has been deleted.