emerge - getting rid of obsolete classes

[Wolfgang Rohdewald]

there are some things in emerge which can not be cleaned
because the API for the old classes based on baseclass
differs from the API for the new classes based on EmergeBase
like buildType which is a string in baseclass but a method
in EmergeBase. 

also those old classes make it more difficult for
new developers to find their way through the source.

and pylint complains about a lot of duplicate code...

I propose to

1. create directy emerge.obsolete parallel to emerge

2. move the deprecated classes and all recipes using them
into emerge.obsolete

3. hope that recipe writers delete some of the
old recipes or port them to the new classes

-- 
Wolfgang