Optimize reading RT130 data

Some tests on large data sets:

	Old code	New code
9BB3_D1.cf	156.14s	32.83s
2016174.9AC4	62.38s	13.61s

Some tests on single files:

	Old code	New code
9BB3_D1.cf/2016326/9BB3/0/000000000_00000000	0.00287s	0.00135s
9BB3_D1.cf/2016327/9BB3/1/030000000_0036EE80	0.177s	0.033s
2016174.9AC4/2016187/9AC4/9/053550000_013EE8A0	0.0026s	0.0013s