- move performance-critical methods to the C layer

- see f4c2bae0118a5afc3f0b4888dee0bfc284162f5a
- refs #5390

PyList_Append increments the item's reference count.

The old approach of storing a pointer to the COMPLEX8TimeSeries in
the GSTLALSnglInspiral struct did not work because we would often
add more than gst_buffer_get_max_memory() memory objects to a buffer.
Consequently, GStreamer would merge the memory objects together,
deallocating the original objects and causing the COMPLEX8TimeSeries
to be freed too early. There is no safe way to use a GstBuffer to
store a pointer to out-of-band auxiliary data.

The new approach is to store the SNR time series samples inline in
the buffer.

- add .random() class method to GSTLALSnglInspiral to test manipulation of SNR memory

- add ability to free SNR time series memory
- free SNR memory after doing gracedb alerts

- in PyArg_ParseTuple()

- to enable triggers to carry SNR snippets with them.