Timing cache works for hello world test.

Timing cache works for hello world test.
Still need
1) detailed CPU (blocking ability in cache)
1a) Multiple outstanding requests (need to keep track of times for events)
2)Multi-level support
3)MP coherece support
4)LL/SC support
5)Functional path needs to be correctly implemented (temporarily works without multiple outstanding requests (simple cpu))

src/cpu/simple/timing.cc:
    Temp hack because timing cpu doesn't export ports properly so single I/D cache communicates only through the Icache port.
src/mem/cache/base_cache.cc:
    Handle marking MSHR's in service
    Add support for getting CSHR's
src/mem/cache/base_cache.hh:
    Make these functions visible at the base cache level
src/mem/cache/cache.hh:
    make the functions virtual
src/mem/cache/cache_impl.hh:
    Rename the function to make sense
src/mem/packet.hh:
    Accidentally clearing the needsResponse field when sending a response back.

--HG--
extra : convert_revision : 2325d4e0b77e470fa9da91490317dc8ed88b17e2