Metacat

Initial checkin of LSID support code for metacat. The LSID support here
provides access to metacat documents through an LSID identifier. The
identifier takes the form:
urn:lsid:ecoinformatics.org:jones:1:1

See http://lsid.sourceforge.net for more details....

Changes in calls made to IndexingQueue class

A version with less number of bugs.

New code for run an indexing queue and indexing thread which runs every 24 hours

Removed the call to indexing function in DBSAXHandler and added a call to indexing function IndexingQueue

removed the indexing code from DBSAXHandler

1. Added code to start the indexing thread.
2. Fixed a bug in the query on xml_nodes and xml_index
3. Added more debug statements
4. Fixed a bug in code which determines namespace

New function which returns the formatted left join query. This is required as Oracle and postgres have different left join syntax

Add more debug info.

Using join query for more efficiency.