Work on #37 Implicit this and method handling. fix bug with method call without arguments.
 Work on #37 Work on command expression. Basic expression handling is broken. Tests will fail.
 Closed #37 Finished command expressions. Decision to get rid of unary minus, plus expressions, as they bring ambiguity. Created #38 to return them.
Merge branch 'feature/parenthesisless_calls_and_command_expression' into develop