Fix the copyright info and formatting in src/podcast and src/core

Fix the copyright info and formatting in src/podcast and src/core
This is next step in fixing all errors from cpplint.py
Also a new copyright automatic updating tool is added to dist.
It's a wip, but I would like to hear some feedback first.
Probably will squash commits into two one for core and one for podcasts.
Still some work is needed.