Log Message:
Update to version 1.33.

Version 1.33
 Charles Hayden fixed a nasty GC bug of the new stack frame, while in
 the process of porting TinyScheme to C++. He also submitted other
 changes, and other people also had comments or requests, but the GC
 bug was so important that this version is put through the door to
 correct it.
Version 1.32
 Stephen Gildea put some quality time on TinyScheme again, and made
 a whole lot of changes to the interpreter that made it noticeably
 faster.