add proper error state to encoder object parsing

fixes #36
Add sloppy_existing_atom as a configuration option for labels
Merge pull request #37 from macintux/friendlier-existing-atom

Add sloppy_existing_atom as a configuration option for labels
rename 'sloppy_existing_atom' to 'attempt_atom'
Add empty rebar.config so that Mix in Elixir projects can build this project as a dependency
Merge pull request #38 from patrickgombert/develop

Add empty rebar.config so that Mix in Elixir projects can build this project as a dependency
remove unesscessary line from README