Converting number bases: any float
	Given: decimal float representation
	Find: binary representation
	value:	13.375ten
		b3	b2	b1	b0		b-1	b-2	b-3
	weight	23	22	21	20		2-1	2-2	2-3
	digit	1	1	0	1	.
					13	.
	Integer part and fractional part are independent.
		1. Convert integer