[Tachyon-list] Memory usage for parsing

On the good side, we have squashed enough bugs to start parsing after the bootstrap.

On the less good side, even with a heap of 256MB we are unable to parse the fibonacci program because too much memory is being allocated.

Maxime thinks we might be able to do it if we optimize the current implementation of the parser (and the rest of the compiler...). I think that given the current implementation, we might need a GC to be able to bootstrap.

To test it on your own machine, simply run "make bt-parser" with the latest revision of the master branch.

I'll try to find how much memory tachyon allocates on d8 when compiling fibonacci.

Erick