Changes in bitbake 1.3.0:
	- add bitbake interactive shell (bitbake -i)
	- refactor bitbake utility in OO style
	- kill default arguments in methods in the bb.data module
	- kill default arguments in methods in the bb.fetch module
	- the http/https/ftp fetcher will fail if the to be 
	  downloaded file was not found in DL_DIR (this is needed
	  to avoid unpacking the sourceforge mirror page)
	- Switch to a cow like data instance for persistent and non
	  persisting mode (called data_smart.py)
	- Changed the callback of bb.make.collect_bbfiles to carry
	  additional parameters
	- Drastically reduced the amount of needed RAM by not holding
	  each data instance in memory when using a cache/persistent
	  storage

Changes in bitbake 1.2.1:
	The 1.2.1 release is meant as a intermediate release to lay the
ground for more radical changes. The most notable changes are:

	-Do not hardcode {}, use bb.data.init() instead if you want to
get a instance of a data class
	-bb.data.init() is a factory and the old bb.data methods are delegates
	-Do not use deepcopy use bb.data.createCopy() instead.
	-Removed default arguments in bb.fetch