_P_r_e_t_t_y _B_r_e_a_k_p_o_i_n_t_s
	
	     pretty(x, n=5)
	
	_D_e_s_c_r_i_p_t_i_o_n:
	
	     pretty returns a sequence of about n equally spaced
	     nice values which cover the range of the values in x.
	     The values are chosen so that they are 1, 2 or 5 times
	     a power of 10.
	
	_E_x_a_m_p_l_e_s:
	
	     pretty(1:15)
	     pretty(1:15 * 2)
	     pretty(1:20)
	     pretty(1:20, n=2)
	     pretty(1:20, n=10)