[COMMIT] store_global/find_global ops

[Melvin Smith]

store_global/find_global ops are in. Added storage of PMCs to PerlHash.

Sample:

new P0, PerlString
set P0, "Melvin\n"
store_global "first", P0
new P0, PerlString
set P0, "Smith\n"
store_global "last", P0
find_global P1, "first"
find_global P2, "last"
print P1
print P2
end

-Melvin