Bugfixes and pretty graphs

Fixed the problem with conc042-045 and concprog002. The bug was in the runtime system code that deals with software transactional memory (STM). Tag bits from a closure pointer weren't getting stripped before it was dereferenced, which was causing misaligned read error. This was a similar bug to one I found at the very start in Printer.c:printClosure.

I also made some pretty graphs of parallel nofib benchmarks. These are just for the T2, which I ran by hand. I'll do comparisons with other platforms tomorrow:





These are both embarrassingly parallel micro benchmarks. This is clear from the fact that the runtime scales almost linearly with the number of threads, until the available hardware is exhausted. Still, it shows its working like it ought to. Horray for +RTS -N64.