FIXING: sro() dies if we pass a code that is valid, but not existis.

If we pass a code that not existis, the response will not have a table, and the fist HTML::TreeBuilder::find will returns undef. The second find will die the script.

Ex: http://websro.correios.com.br/sro_bin/txect01$.Inexistente?P_LINGUA=001&P_TIPO=002&P_COD_LIS=RA189611162BR
Fixing wrong variable name on English translated example
Retirando Try::Tiny

Works well. But I think it deserves unit tests yet.
Trying to obey Buss Code Standard
better now
Better code organization
Merge pull request #2 from leobetosouza/master

We dont want to die if the code dont existis in Correios db