Move main control from C++ into Python.

Move main control from C++ into Python.
User script now invokes initialization and
simulation loop after building configuration.
These functions are exported from C++ to Python
using SWIG.

SConstruct:
    Set up SWIG builder & scanner.
    Set up symlinking of source files into build directory
    (by not disabling the default behavior).
configs/test/test.py:
    Rewrite to use new script-driven interface.
    Include a sample option.
src/SConscript:
    Set up symlinking of source files into build directory
    (by not disabling the default behavior).
    Add SWIG-generated main_wrap.cc to source list.
src/arch/SConscript:
    Set up symlinking of source files into build directory
    (by not disabling the default behavior).
src/arch/alpha/ev5.cc:
src/arch/alpha/isa/decoder.isa:
src/cpu/o3/alpha_cpu_impl.hh:
src/cpu/trace/opt_cpu.cc:
src/cpu/trace/trace_cpu.cc:
src/sim/pseudo_inst.cc:
src/sim/root.cc:
src/sim/serialize.cc:
src/sim/syscall_emul.cc:
    SimExit() is now exitSimLoop().
src/cpu/base.cc:
    SimExitEvent is now SimLoopExitEvent
src/python/SConscript:
    Add SWIG build command for main.i.
    Use python/m5 in build dir as source for zip archive...
    easy now with file duplication enabled.
src/python/m5/__init__.py:
    - Move copyright notice back to C++ so we can print
    it right away, even for interactive sessions.
    - Get rid of argument parsing code; just provide default
    option descriptors for user script to call optparse with.
    - Don't clutter m5 namespace by sucking in all of m5.config
    and m5.objects.
    - Move instantiate() function here from config.py.
src/python/m5/config.py:
    - Move instantiate() function to __init__.py.
    - Param.Foo deferred type lookups must use m5.objects
    namespace now (not m5).
src/python/m5/objects/AlphaConsole.py:
src/python/m5/objects/AlphaFullCPU.py:
src/python/m5/objects/AlphaTLB.py:
src/python/m5/objects/BadDevice.py:
src/python/m5/objects/BaseCPU.py:
src/python/m5/objects/BaseCache.py:
src/python/m5/objects/Bridge.py:
src/python/m5/objects/Bus.py:
src/python/m5/objects/CoherenceProtocol.py:
src/python/m5/objects/Device.py:
src/python/m5/objects/DiskImage.py:
src/python/m5/objects/Ethernet.py:
src/python/m5/objects/Ide.py:
src/python/m5/objects/IntrControl.py:
src/python/m5/objects/MemObject.py:
src/python/m5/objects/MemTest.py:
src/python/m5/objects/Pci.py:
src/python/m5/objects/PhysicalMemory.py:
src/python/m5/objects/Platform.py:
src/python/m5/objects/Process.py:
src/python/m5/objects/Repl.py:
src/python/m5/objects/Root.py:
src/python/m5/objects/SimConsole.py:
src/python/m5/objects/SimpleDisk.py:
src/python/m5/objects/System.py:
src/python/m5/objects/Tsunami.py:
src/python/m5/objects/Uart.py:
    Fix up imports (m5 namespace no longer includes m5.config).
src/sim/eventq.cc:
src/sim/eventq.hh:
    Support for Python-called simulate() function:
    - Use IsExitEvent flag to signal events that want
    to exit the simulation loop gracefully (instead of
    calling exit() to terminate the process).
    - Modify interface to hand exit event object back to
    caller so it can be inspected for cause.
src/sim/host.hh:
    Add MaxTick constant.
src/sim/main.cc:
    Move copyright notice back to C++ so we can print
    it right away, even for interactive sessions.
    Use PYTHONPATH environment var to set module path
    (instead of clunky code injection method).
    Move main control from here into Python:
    - Separate initialization code and simulation loop
    into separate functions callable from Python.
    - Make Python interpreter invocation more pure (more
    like directly invoking interpreter).
    Add -i and -p flags (only options on binary itself;
    other options processed by Python).
    Import readline package when using interactive mode.
src/sim/sim_events.cc:
    SimExitEvent is now SimLoopExitEvent, and uses
    IsSimExit flag to terminate loop (instead of
    exiting simulator process).
src/sim/sim_events.hh:
    SimExitEvent is now SimLoopExitEvent, and uses
    IsSimExit flag to terminate loop (instead of
    exiting simulator process).
    Get rid of a few unused constructors.
src/sim/sim_exit.hh:
    SimExit() is now exitSimLoop().
    Get rid of unused functions.
    Add comments.

--HG--
extra : convert_revision : 280b0d671516b25545a6f24cefa64a68319ff3d4