UDR libraries need to be stored in metadata table as a blob

This is one of many  infrastructure changes for SPJs that was planned. 

• Store UDR libraries in BLOBs   

• Add BLOB column to library metadata table
• Change CREATE LIBRARY command to store library in BLOB
• Change library file names to include the timestamp (so updating a library changes the name)
• Add a cache for libraries (a new directory, $TRAF_HOME/udr/public/lib)
• Change UDR code to read library from the metadata table when not in cache
• Upgrade support