vector address according to cpu mode.
(interrupts_initialize): Move reset portion to the above.
(interrupt_names): New table to give a name to interrupts.
(idefs): Handle pulse accumulator interrupts.
(interrupts_info): Print the interrupt history.
(interrupt_option_handler): New function.
(interrupt_options): New table of options.
(interrupts_update_pending): Keep track of when interrupts are
raised and implement breakpoint-on-raise-interrupt.
(interrupts_process): Keep track of when interrupts are taken
and implement breakpoint-on-interrupt.
* interrupts.h (struct interrupt_history): Define.
(struct interrupt): Keep track of the interrupt history.
(interrupts_reset): Declare.
(interrupts_initialize): Update prototype.
* m68hc11_sim.c (cpu_reset): Reset interrupts.
(cpu_initialize): Cleanup.
* dv-m68hc11tim.c (cycle_to_string): New function to translate
the cpu cycle into some formatted time string.
(m68hc11tim_print_timer): Use it.
* dv-m68hc11sio.c (m68hc11sio_info): Use cycle_to_string.
* dv-m68hc11spi.c (m68hc11spi_info): Likewise.
* interrupts.c (interrupts_info): Likewise.
* m68hc11_sim.c (cpu_info): Likewise.
