[CVS ci] method cache

[Leopold Toetsch]

Here are recent numbers with the new method cache:

$ perl tools/dev/parrotbench.pl -c=parrotbench.conf -b=^oo
Numbers are relative to the first one. (lower is better)
        parrotj parrot  parrotC perl-th perl    python  ruby
oo1     100%    104%    106%    98%     83%     54%     70%
oo2     100%    103%    105%    99%     83%     49%     71%
oofib   100%    118%    118%    105%    91%     60%     58%
W/o method cache oo2.pl was at 103% so this is the overhead of the 
cache. oofib (method calls mainly) are now faster then in threaded perl.

Above numbers are from an optimized build, excecpt cgoto or CGP (which 
takes too long on my box).

leo