RBTools would crash when Unicode characters were specified on the
command line, due to a logging statement that tried converting the byte
strings into a Unicode string. This was happening because our RBT_MAIN
constant was a Unicode string, and thus all remaining strings in argv
were being converted (improperly) to Unicode as well.

This changes RBT_MAIN to be a byte string, allowing string concatenation
to work properly. It also fixes some argument lookups and the logging
statement to properly decode to a Unicode string.

Posted a change using Chinese characters as the review request description.

Instead of errors and crashes, I got proper debug output and the change

posted.