Bumped version to 0.1.1.
Created a new abstract interface for atom caching.
Updated the documentation for generic function GET-ATOM. It should return two values.
Added MOCK-ATOM-CACHE for testing encoding/decoding of cached atoms.
Added file for unit testing ENCODE. Added test for encoding atoms with atom caching.
Added unit test for decoding atom cache references.
Added proper conditions for decoding errors for atom cache references.
Removed BYTES-TO-STRING and STRING-TO-BYTES.
Revert "Removed BYTES-TO-STRING and STRING-TO-BYTES."

This reverts commit 31c240ffd0766d4b506b2cc43379b3114882a697.
Made it easier to run the unit tests.