PyPANDA `dump_stack` word_size is incorrect

[fengjian]

I think word_size = int(self.panda.bits/8)

  def dump_stack(self, cpu, words=8):
        '''
        Print (telescoping) most recent `words` words on the stack (from stack pointer to stack pointer + `words`*word_size)
        '''

        base_reg_s = "SP"
        base_reg_val = self.get_reg(cpu, self.reg_sp)
        word_size = int(self.panda.bits/4)  

        for word_idx in range(words):
            val_b = self.panda.virtual_memory_read(cpu, base_reg_val+word_idx*word_size, word_size)
            val = int.from_bytes(val_b, byteorder='little')
            print("[{}+0x{:0>2x} == 0x{:0<8x}]: 0x{:0<8x}".format(base_reg_s, word_idx*word_size, base_reg_val+word_idx*word_size, val), end="\t")
            telescope(self.panda, cpu, val)

[AndrewFasano]

Fixed by #1006