ASFBAH: Harvester threaded and using multiprocessing (starmap) and others

	* Bug Fixes

	* Exceptions management

	* Harvester class : It the class in charge of harvesting projects
	  for statistics. It is doing all steps from downloading to
	  the injection into the database

   	  The class has an internal timer to wake it every n seconds.
	  For every n seconds, it checks if it needs to harvest something,
	  based on the harvesting configuration file.

	  It pops a pool of process to parallelized, the harvest step !
	  Because we are using starmap new requirement is now Python 3.3
	  or higher

	* restructuration of the database architecture

	* log class for store log into the database