DO NOT MERGE - changes to pom.xml

For speed of testing/development, the only test run is PGDOIDatabaseTest.java
DO NOT MREGE - Explicitly set the dspace.cfg when testing

The DSpace JUnit tests do not use the config file and get no database access
Filled out tests.  Added stub for concurrency test
Initial tests for concurrency
Cleanup/refactoring
Use Assert class
Removed savepoints and rollbacks
Remove assertions from DOI task
Cleaned up context handling
Fixed bug of 1 or 2 left due to modifying the loop max
Made operations synchronized

Tests pass
If putGetRemove are not in synchronized block, get SQL errors.
Running two at once results in SQL Duplicate keys and test fails because it's making assertions that can be invalidated by other threads
Remove assertions and synchronized on putGetRemove

Assertions not valid in this test - multiple threads may be altering
the same DOIs in between method calls, which does not constitute a
failure.

Removing synchronized lets us confirm the DB operations don’t need to
be in a synchronized block
Rewrote context handling

Each operation instantiates and cleans up a context, rather than
keeping a single context around
Implemented dump/dumpTo

Copied from DOIDatabase, and using getALL()
Test case for dump
Include URL column in DOI queries

This was missing from queries, so fetched DOIs had no URL.  dump test
case caught it.
Don't check for source url in testDump
Implemented testDumpTo

Extracted shared code from testDump that verifies DOI is in the dump
output.
Remove TODO about throwing a DOIFormatException
If the parameter is a DOI object, it can't be formatted badly