adding 'more' command; raising version to beta2

For implementing irb-like console in the IDE we need to know if current expression (multiline expression) is finished or we should await for more input. 'more' command was added, which does not use the debugger, but uses the exact ruby version (lang-level) used on the debugger side for parsing expressions.
it looks like you do not need/use line number, so I'd suggest to simplify the code to use just last_line instead of last_statement.