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)

- temporary hack, remove after O2

- to an error message

- forgot one spot in plotpsd.py
- refs #5603

idq_multirate_datasource.py: fixed normalization in downsampler, fixed dc offset that appears in certain channels