gstlal-calibration:  New plotting script in tests/check_calibration/plot_transfer_function.py to plot transfer functions.

gstlal-calibration:  Improved methods for doing noise subtraction multiple times using different witnesses in series.

- test_commpn.py:  Seeking pipeline seems to work now.
- pcal-to-darm plotting script:  now works in new setup.
- gstlal_compute_strain: removed stray dq_epics variables

gstlal-calibration:  Using Makefile to generate directories with filters when needed, but these directories are in .gitignore, so they will not be part of the gstlal repo.

gstlal_compute_strain:  Split the PUM and UIM stages of the actuation and calculate kappa_PUM and kappa_UIM separately and apply them.

gstlal_compute_strain:  pipeline searches for filters file given only file name in config file.  Order of preference for which filters to use is:
1) Filters from the calibration SVN (that is, those found in /ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/*/GDSFilters/)
2) Filters in the user's home directory in a subdirectory called GDSFilters
3) Filters in the user's home directory in any subdirectory

- tests/check_calibration:  Caitlin Rose's Automated testing scripts and Makefiles for doing calibration tests.
- gstlal_compute_strain:  Don't demodulate the pcal channel again to compute SRC detuning if re-using the ~30 Hz pcal line
- lal_transferfunction:  1. Bug fixes for median of transfer functions.  2. Option to compute first transfer function asap at start of stream.  3. Use GPS time to decide when to update transfer functions so that output becomes independent of start time asap.
- tests/check_calibration:  Added plotting script and Makefile example for plotting time series of \DeltaL / pcal at calibration line frequencies.
- config_files:  Example config file for offline calibration with noise subtraction.

Added in example configuration file for possible future use