Added support for submitting jobs to the Open Science Grid

This PR updates bilby_pipe to support running on the Open Science Grid. The highlights are

• the bilby_pipe command-line script now supports the --osg option
• updated options for vanilla-universe checkpointing (cc @james-clark)

To support the above, I chose to do a bit of restructuring in the relevant methods to clean up how the submit files are generated, including

• moved out/err/log file path options to a method
• moved checkpointing options to a method
• moved file transfer options to a method and fixed directory names for transfer_output_files
• track extra_lines as a list, not a monolithic str (this is natively supported by pycondor anyway)
• support appending requirements to self.requirements (required for OSG options)

Fixes #103 (closed).

bilby_pipe/data_files/128s.prior

@@ -7,7 +7,7 @@ tilt_1 = Sine(name='tilt_1', boundary='reflective')
 tilt_2 = Sine(name='tilt_2', boundary='reflective')
 phi_12 = Uniform(name='phi_12', minimum=0, maximum=2 * np.pi, boundary='periodic')
 phi_jl = Uniform(name='phi_jl', minimum=0, maximum=2 * np.pi, boundary='periodic')
-luminosity_distance = bilby.gw.prior.UniformComovingVolume(name='luminosity_distance', minimum=1, maximum=5e2, unit='Mpc', boundary='reflective')
+luminosity_distance = bilby.gw.prior.UniformSourceFrame(name='luminosity_distance', minimum=1, maximum=5e2, unit='Mpc', boundary='reflective')
 dec = Cosine(name='dec', boundary='reflective')
 ra = Uniform(name='ra', minimum=0, maximum=2 * np.pi, boundary='periodic')
 theta_jn = Sine(name='theta_jn', boundary='reflective')