For non-GR known pulsar searches allow emission at the rotation frequency

Description

The Bayesian known pulsar parameter estimation code currently can allow non-GR modes if you assume emission only at twice the rotation frequency. This MR adds additional non-GR amplitude parameters (prefixed with _F) to the model that can be used to parameterize a non-GR signal at the rotation frequency.

@max-isi - take a look and see if this looks ok (or if you think there's a better naming convention than _F). Note: I've not changed the set_nonGR_model_parameters() function in ppe_models.c, so you may want to see if that also needs an update.

API Changes and Justification

Backwards Compatible Changes

• This change introduces no API changes
• This change adds new API calls

Backwards Incompatible Changes

• This change modifies an existing API
• This change removes an existing API

Review Status

To be checked by @max-isi.

The code compiles and the new parameters are correctly read in. I've added them to the ReadTEMPOFileTest test code and it passes. This can also be seen by creating a par file containing (called, e.g., nongr.par):

PSRJ J1000-1000
RAJ 10:00:00.0
DECJ 10:00:00.0
F0 100.1
H0 1e-24
HPLUS 0.5e-24
HPLUS_F 2e-24
HCROSS_F 3e-24
HVECTORX_F 1e-24
HVECTORY_F 3.4e-25
HSCALARB_F 2.3e-25
HSCALARL_F 1.2e-25
PSITENSOR_F 0.1
PHI0TENSOR_F 0.2
PSISCALAR_F 0.3
PHI0SCALAR_F 0.4
PSIVECTOR_F 0.5
PHI0VECTOR_F 0.6

and reading it in with:

from lalpulsar.PulsarParametersWrapper import PulsarParametersPy                         
par = PulsarParametersPy('nongr.par')
par.as_dict()                                                                            
{'PSRJ': 'J1000-1000',
 'RAJ': 2.617993877991494,
 'DECJ': 0.17453292519943295,
 'F': array([100.1]),
 'H0': 1e-24,
 'HPLUS': 5e-25,
 'HPLUS_F': 2e-24,
 'HCROSS_F': 3e-24,
 'HVECTORX_F': 1e-24,
 'HVECTORY_F': 3.4e-25,
 'HSCALARB_F': 2.3e-25,
 'HSCALARL_F': 1.2e-25,
 'PSITENSOR_F': 0.1,
 'PHI0TENSOR_F': 0.2,
 'PSISCALAR_F': 0.3,
 'PHI0SCALAR_F': 0.4,
 'PSIVECTOR_F': 0.5,
 'PHI0VECTOR_F': 0.6}

where the values match up as expected.

cc @karl-wette @david-keitel