synth codes: add per-IFO noise weights and ant-pat output

 -just overall per-IFO SX/S, no per-SFT variation
 -user input as --sqrtSX,
  parsed with XLALParseMultiNoiseFloor(),
  internal conversion to noiseweights with new function
  XLALComputeConstantMultiNoiseWeightsFromNoiseFloor()
 -absolute values still don't have any influence, only ratios count
 -noise weights handling through XLALComputeMultiAMCoeffs()
 -per-IFO antenna pattern matrix output in params file
 -simply use results from multiAMBuffer->multiAM
 -ABCD might be normalized differently, but detM is invariant
 -synthesizeTransientStats compatibility changes
 -refs #1334
synthLV: improve file output

 -columns header line
 -include alpha, delta
 -cleaned up code
 -refs #1334
new test script for lalapps_synthesizeLVStats

 -refs #1334