Add lots of unique tags to error log messages

Cleanup effort in prep for GA push: Trim trailing whitespace... no func change

mpm_common.c implements a handful of config directives; the related state has to be re-initialized to the default values at pre-config time, but that was handled inconsistently by the MPMs, resulting in unexpected behavior when some of the directives were removed across restart move that necessary initialization from the MPMs to common code run from core's pre-config; MPMs that need to override defaults can do so by running after core's pre-config (the NetWare MPM now does that) the DEFAULT_MAX_REQUESTS_PER_CHILD compile setting wasn't useful enough to keep the simple MPM wasn't consistent in which of these directives were respected and which weren't, and that hasn't changed (see procmgr.max_requests_per_child vs. ap_max_requests_per_child)

Use the new APLOG_USE_MODULE/AP_DECLARE_MODULE macros everywhere to take advantage of per-module loglevels

rename the new retained-data APIs to ap_retained_data_create()/ap_retained_data_get(), for better consistency with existing APIs (e.g., slotmem) don't bother changing the MMN, which doesn't reflect recent -dev changes anyway

change the allocation path for the simple MPM's retained data, as a dynamically loadable MPM can't use the rewrite-args hook (note across the table: the hooker hook has no retcode feedback, so I didn't init the data there)

header file tweaks required for compilability

Clean up thread and process number defaults for simple mpm. - Before, simple wouldn't start without explicit config, because default numbers were 0 - log messages "more" and "less" were misleading

Convert events to have an associated pool. * server/mpm/simple/simple_types.h (simple_timer_t): Add Pool and a pointer to the associated simple core. (simple_core_t): Remove dead timer ring, no recycling of timer events for now. * server/mpm/simple/simple_event.h: Update register_timer signature with pool. * server/mpm/simple/simple_event.c (simple_register_timer): Allocate the event structure out of the pool, and when this pool is destroyed, unregister the timer. (simple_timer_run): New util function for running a timer and cleaning up the pool callbacks. * server/mpm/simple/simple_core.c (simple_core_init): Remvoe dead timer ring * server/mpm/simple/simple_run.c (simple_main_setup_timers): Pass in pool to register call. (simple_timer_invoke): Use new simple_timer_run function. (simple_child_loop): Remove dead timer ring. * server/mpm/simple/simple_io.c (simple_io_process): Pass in pool when registering timers.

Move creation of the pollcb object to after we fork(), since kqueues don't persist across fork(). (huh, didn't know that before)

Basic support for spawning children porcesses via fork() and killing them with kill().

reindent according to our coding style: <http://httpd.apache.org/dev/styleguide.html> for i in `ls *.h *.c`; do indent -i4 -npsl -di0 -br -nce -d0 -cli0 -npcs -nfc1 -nut ${i}; done

Add a work in progress, a completely new, "Simple MPM".