style: [patch 1/22] use /r/3648/ to reorganize includes

sim: Add relative break scheduling

Add schedRelBreak() function, executable within a debugger, that sets a
breakpoint by relative rather than absolute tick.

sim: Add ability to break at specific kernel function

Adds a GDB callable function that sets a breakpoint at
the beginning of a kernel function.

config: Add a --without-python option to build process

Add the ability to build libgem5 without embedded Python or the
ability to configure with Python.

This is a prelude to a patch to allow config.ini files to be loaded
into libgem5 using only C++ which would make embedding gem5 within
other simulation systems easier.

This adds a few registration interfaces to things which cross
between Python and C++. Namely: stats dumping and SimObject resolving

sim: simulate with multiple threads and event queues
This patch adds support for simulating with multiple threads, each of
which operates on an event queue. Each sim object specifies which eventq
is would like to be on. A custom barrier implementation is being added
using which eventqs synchronize.

The patch was tested in two different configurations:
1. ruby_network_test.py: in this simulation L1 cache controllers receive
requests from the cpu. The requests are replied to immediately without
any communication taking place with any other level.
2. twosys-tsunami-simple-atomic: this configuration simulates a client-server
system which are connected by an ethernet link.

We still lack the ability to communicate using message buffers or ports. But
other things like simulation start and end, synchronizing after every quantum
are working.

Committed by: Nilay Vaish

sim: Clarify the difference between tracing and debugging

This patch changes the name the command-line options related to debug
output to all start with "debug" rather than being a mix of that and
"trace". It also makes it clear that the breakpoint time is specified
in ticks and not in cycles.

sim: have a curTick per eventq
This patch adds a _curTick variable to an eventq. This variable is updated
whenever an event is serviced in function serviceOne(), or all events upto
a particular time are processed in function serviceEvents(). This change
helps when there are eventqs that do not make use of curTick for scheduling
events.

event: minor cleanup
Initialize flags via the Event constructor instead of calling
setFlags() in the body of the derived class's constructor. I
forget exactly why, but this made life easier when implementing
multi-queue support.

Also rename Event::getFlags() to isFlagSet() to better match
common usage, and get rid of some unused Event methods.

Debug: Add a function to cause the simulator to create a checkpoint from GDB.

debug: create a Debug namespace

debug: Move debug_break into src/base

gdb: add a debugging function that enters the python interpreter.

eventq: convert all usage of events to use the new API.
For now, there is still a single global event queue, but this is
necessary for making the steps towards a parallelized m5.

style: Remove non-leading tabs everywhere they shouldn't be. Developers should configure their editors to not insert tabs

RemoteGDB: add an m5 command line option for setting or disabling remote gdb.

Make the Event::description() a const function

Major changes to how SimObjects are created and initialized. Almost all
creation and initialization now happens in python. Parameter objects
are generated and initialized by python. The .ini file is now solely for
debugging purposes and is not used in construction of the objects in any
way.

Expose debugBreakCycle through swig and get rid of
the Debug param context

remove extern "C" from the functions we all from gdb. This isn't requried and trips up GDB sometimes when i thinks the extern
name should be mangled, but it isn't

Updated Authors from bk prs info

New directory structure:
- simulator source now in 'src' subdirectory
- imported files from 'ext' repository
- support building in arbitrary places, including
outside of the source tree. See comment at top
of SConstruct file for more details.
Regression tests are temporarily disabled; that
syetem needs more extensive revisions.

SConstruct:
Update for new directory structure.
Modify to support build trees that are not subdirectories
of the source tree. See comment at top of file for
more details.
Regression tests are temporarily disabled.
src/arch/SConscript:
src/arch/isa_parser.py:
src/python/SConscript:
Update for new directory structure.