* Allow reseting the stream of smt2::scanner
* Put the parser of parse_smt2_commands in the cmd_context
* Move parser streams to cmd_context
* Move parser fields from cmd_context to api::context
* Move forward declarations from cmd_context.h to api_context.h
* Change parse_smt2_commands_with_parser to use *& instead of **
* Add tests for Z3_eval_smtlib2_string
* Don't reuse the streams in Z3_eval_smtlib2_string
* Fix indentation
* Add back unnecessary deleted line
Co-authored-by: Nuno Lopes <nuno.lopes@tecnico.ulisboa.pt>
