Major rewrite, fixing some bugs an improving performance. Multiple not-backwards compatible changes! But porting should be straight forward:) Performance and memory use improvements from redesign to use bit masks to keep track of set envs. Allow specifying env through 'most specific group', where a group which contains a subset of envs contained in another group is considered more specific. Replaced 'valid_envs' arg with 'env_factory' arg, all defined envs are now valid!
Envs json dump
Allow users to override 'setattr' while still getting correct file:line info  - public 'caller_file_line'  - mc_caller_file_name and mc_caller_line_num args on setattr Fix - assignment with different type showing error file:line in multiconf instead of user code
Improved error message for unspecific group value assignment Performance improvement from not collection values which can be gotten from kwargs in case of error
Envs performance optimizations