This reverts commit 5f9d2a3f.

and fixes it by making adjustments to pipeio.py, reference_psd.py, inspiral.py

- and add a safety check for invalid IMR approximants

- filter allowed_rates with one loop

- make add_quadrature_phase a static method

- also edit a comment and fix some whitespace

- Multiplies incoming real float stream by exp(i*2*pi*line_frequency*t), where line_frequency is a property to set to a calibration line frequency. This allows for the extraction of the calibration factors, "kappa's".

-Also added to gstlal-calibration/tests/test_common.py and lal_logicalundersample_test.py.

-Now written in C. Added /gstlal-calibration/tests/lal_logicalundersample_test.py for testing. Also small change to lal_constantupsample.

- OK for control buffers to have 0 length

- unary & (address of) comes after "->" and "." operators

- Included lal_constantupsample_test.py for testing, updated test_common.py in gstlal-calibration to match what is in gstlal.