new unified vector-comparison functions for REAL4- and COMPLEX8 vectors

- XLALCompare[REAL4|COMPLEX8]Vectors(): output a struct detailing
  different comparison metrics computed (can be easily extended in the future),
  and allows checking against a given set of tolerances for those metrics
- useful for comparing Fstat-vectors, Fa-vectors and SFTs
renamed and extended TestLFTandTSutils.c to LFTandTSutilsTest

- test only XLALSFTVectorToLFT() directly, instead of
  XLALSFTVectorToCOMPLEX8TimeSeries(), which doesn't have a direct comparison
- refs #535
LFT and CFS tests: use new vector-comparison functions

- replace individual 'manual' comparisons in each case
- added debug-output of Fstat-vectors in ComputeFstatTest.c
  if 'info' bit is set
ComputeFstat_Resamp: more cleanup and internal simplification

- removed some more old-API vestiges
- pure restructuring, no content changes
- refs #535
ComputeFstat_Resamp: simplify internal handling of buffer

- refs #535
ComputeFstat_Resamp: simplified and allow returning more Fstat quantities

- simplified calculation of multi-IFO Fstat values, and slightly
  reduced memory footprint
- activated returning FAFB, FAFB_PER_DET
- return proper Mmunu matrix
- refs #535
LFTandTSutils: simplify math using C99 complex operations

- refs #535
LFTandTSutils: style cleanup and modernized, no content changes

- use 'XLAL style' consistently
- refs #535
LFTandTSutils: global definition of NhalfNeg|Pos() macros

- refs #535
XLALSFTVectorToLFT: interally use XLALSFTVectorToCOMPLEX8TimeSeries()

- avoid lots of code duplication
- refs #535