Refactor changes and added state handling of peers and routers. See detailed notes.

New Changes:
* Added isConnected in routers table to track if the BMP router is connected.
* Added state handling for bgp peers
* Added db_timestamp to rib table to enable purging of old rib entries that are no longer needed
* Added signal handler to properly close DB connections and to update routers so they
  they are not connected due to openbmp being stopped.
* DB is now using v1.3-pre1

Refactor:
* Fixed database documentation to detail behaviors and latest updates
* Refactored timestamps to match what is documented. Most are using the BMP peer
  header timestamp
* Moved client threading functions to separate source
* Changed peer adds to use in memory map caching instead of relying on mysql on duplicate
  update handling
* Changed BMPServer.cpp to BMPListener.cpp and BMPReader.cpp for better handling
* Corrected some logging items
* Add disconnect router method to handle bmp term message as well as abnormal disconnects