Metacat

1. Changed teh access modifier from public to private for variables
2. Added a new variable for nodedatanumerical
3. added a new constructor

Moved printMessage statements to inside the if loop so that they are not printed each time getInstance is called

Using xml_path_index instead of xml_index to find documents which havnt been indexed.

Replaced hardcoded namespaces with variable defined in metacat.properties

Changed logMetacat to be a local variable in MetaCatServlet to avoid any potential threading issues.

Metacat has had problems with threading issues when accessed from ecogrid. These problems may stem from the use of shared global variables within the servlet that are not protected against threading problems. We used a lot of these, which I am eliminating in this commit. Besides final variables used as constants (which are not a problem), now there are only three unprotected variables (sessionHash, logMetacat, and conn) which are harder to eliminate. I will be discussiong this with Sid tomorrow to see how to eliminate them.

Fixed the bug that replicate data file failed that the documents records wouldn't be deleted.

the parameter of method getRevisionTableReList is docidWithoutRev.

Fixed bug that data file upload failed, record couldn't be deleted.

Bug #2207: Implementation of the Metacat Advanced Search engine.