Merge remote-tracking branch 'origin/sam_ubuntu1210' into sam_177
Merge branch 'next' into sam_177
Merge branch 'next' into sam_177
Made secs_to_ticks take a time_t instead of double.
Made the timing code no longer use void-pointer context variable callbacks.
Merge branch 'next' into sam_177
Deleted the db_thread_info.hpp header (and put get_num_db_threads in utils.hpp).  Finally.
Merge branch 'next' into sam_177
Made the new priority queue timer/timer_provider stuff compile.  Does not work.
Merge branch 'next' into sam_177
Make thread pool send initial_message with insert_external_message.

- That way we write to the notification file descriptor.
- Before, the timer_provider ran an interval timer that would happen to cause the first wake-up and cause the initial message to be run.
Removed speculative cancel_timer assertion about it being an interval timer.  The writeback trips the assertion.
Made the signal_timer_t handle zero-length timeouts by immediately pulsing.
Merge branch 'next' into sam_177
Merge branch 'next' into sam_177
Replaced some numeric literals with the macros MILLION, THOUSAND, etc.
Got the timer_signal_provider compiling, and maybe working.
Made us set callback to NULL when unscheduling a oneshot event.
Merge branch 'next' into sam_177
Merge branch 'next' into sam_177