This commit involves following set of changes:
  - log4j properties file included in vcenter-plugin package
  - log4j.properties file passed as argument to java
  - logging messages cleanup.

  - VncDB & VCenterDB Sync happens only once during startup.
  - After that every 4 sec, VCenter DB is read and compared
    against 4 sec old Dataase. If there are differneces,
    appropriate actions (Add/Del VN/VM) taken.

  - VCenter Event Nofification code added. It's not integrated yet.