#408 weighted_frequency method returns bogus frequencies
In the python interface, the weighted_frequency method on Integration objects returns bogus frequencies. By "bogus" I mean "not equal to the frequency numbers in PSRFITS files" and also "not necessarily in the range accepted by the receiver". An example:
print [I.weighted_frequency(i) for i in range(F.get_nchan())][:10]
print F_fits['SUBINT'].data['DAT_FREQ'][0][:10]
[1510.6408344515858, 1510.6408344515858, 1510.6408344515858, 1510.6408344515858, 1510.6408344515858, 1510.6408344515858, 1510.6408344515858, 1510.6408344515858, 1510.6408344515858, 1512.784289665465]
[ 1102.34375 1108.59375 1114.84375 1121.09375 1127.34375 1133.59375
1139.84375 1146.09375 1153.90625 1158.59375]
Also, the channel center frequencies are not available; as long as there are no gaps in the band they can be computed from the bandwidth and center frequency, but some files seem to contain non-contiguous channels.
