moved interrupt routine to main loop

#include <avr/io.h>
#include <avr/interrupt.h>
#include <util/delay.h>

int extratime=0;
int num_presses=0;

int main(void)
{
  DDRD = 0b11111111;
  PORTD = 0b00000000;
  DDRB = 0b11110000;
  PORTB = 0b00000000;
  char button_state;

  TCCR1B |= (1 << CS12) | (1 << CS10);

  while(1)
  {
    if (bit_is_clear(PINB, 0)) //button is pressed
    {
      if (button_state==0) //was previously not pressed)
      {
        num_presses++;
      }
      button_state=1;
    }
    else
    {
      if (button_state==1) //was previously pressed
      {

      }
      button_state=0;
    }

    if (TCNT1 >= 15625)
    {
         if (extra_time == 5)
         {
         PORTD = num_presses;
             extra_time = 0;
         }
         else
         {
             ++extra_time;
         }
         TCNT1 = 0;
    }
  }
}