Remove deprecated code for Version 3.0

[bhazelton]

trafficstars

• remove support the old array shapes
• remove support for old phasing including the phase_type, phase_center_ra/dec, frame, epoch attributes
• Always require spw_id_array (so can remove the flex_spw boolean)
• Update the tutorials to remove text about these deprecated items.

[bhazelton]

Also remove gps_a, gps_b, e_squared, e_prime_squared from utils.pyx

[bhazelton]

Done in #1437