Remove Charon since it is not needed anymore

This fixes issue #35
Add .dir-locals.el with tab settings for Emacs
Merge pull request #46 from stoewer/master

Unit test for nix::Block (part of issue #25)

Tested locally.
Move old unit tests for Source
Add assignment operator for nullptr_t to Source

Add missing operator<< to Source
Method testOperators was not registered on TestBlock
Started unit test for nix::Source