gstlal_compute_strain:  Commented out 2 lines as a temporary fix to get SRC detuning calculation to work.

calibration_parts.py:  Added new function remove_lines.

- use fewer intermediate variables when parsing caches
- refs #5589

- this patch removes use of the glue.lal.Cache class
- refs #5589

- fall-through is intended, but new gcc 7 complains about it

- found by new implicit fall-through warning in gcc 7

- the occurrence of an error in the start() method was not being reported to the calling code

- package dependencies change following reorganization of GDS packages
- now require only gds-lowlatency package

- gets doctest working

Some debugging on gstlal_clean_strain (although it still doesn't run)

Added in example configuration file for possible future use

Adding in lal_fcc_update element that computes a new cavity pole filter and sends out message when new filter is computed

- also reduce the line width of both plots to cause the PSD plot to hide fewer features

- introduces summarize_coinc_xmldoc()

- axes_plot_psds() generates a PSD plot on an axes object.
- plot_psds() is now only a wrapper that creates a figure object and uses axes_plot_psds() to populate its one set of axes with the PSD plot.
- this allows the PSD plot to be added to other, multi-axes, figures in the future.

- change the range of frequencies over which the spectrum min/max is measured to [10, 900] from [10, 1000]
- choose the lower bound of the y-axis by dividing the spectrum min by 3 before taking the log and the floor to provide some extra padding below the spectrum
- increase the number of y axis ticks and add minor ticks to the y axis

matplotlib plotting error (axes.plot cannot take markersize = None, at
least not in version 1.4.2, the current CIT version)