Major read buffer improvement

What's Changed

• Removed error suppression in ReadBuffer by @EinKrebs in https://github.com/EinKrebs/json/pull/10
• Rewrited buffer to make enable repeating read & added tests by @EinKrebs in https://github.com/EinKrebs/json/pull/11

Full Changelog: EinKrebs/json@v0.2.1...v0.2.2