Added minitest tests for zone and signed_params
Added quick usage guide
Corrected hash syntax to pass tests for ruby 1.8 ...
Added UTF-8 encoding
Merge pull request #2 from nicolasbrechet/tests

Added:
* minitest tests for zone and signed_params
* quick usage guide
Added CodeClimate test coverage
Merge pull request #3 from nicolasbrechet/master

Converting shindo tests to minitest