FlatLatticeTiling: replace bounds functions with built-in equations

- bounds equation given in documentation to XLALSetFlatLatticeBound()
- new internal functions FLT_GetBound[s]() and FLT_TransformBound()
- modified implementation of bounds in XLALSetFlatLatticeConstantBound(),
  XLALSetFlatLatticeEllipticalBounds() (with some simplifications),
  XLALSetFlatLatticeF1DotAgeBrakingBound() and
  XLALSetFlatLatticeF2DotBrakingBound()
- CFSv2 FLT square grids (8) are unmodified, but age-braking indices (9)
  return slightly different points due to different numerical order of
  bound computations, so disable this test for now
- comment out XLALNearestFlatLatticePointToRandomPoints() for now
testCFSv2_FLTgrids.sh: update reference grid 9 and re-enable test

- see previous commit
Remove unnecessary XLAL_CHECK on snprintf()
Fix IHS to h0
Comments added
Updated scripts to use better command line arguments
Changed to 520 Hz
Many updates:

 - Added AVX functions in vectormath and tests in testVectorMath
 - Changed normalization for signal only to one based on strain of detector instead of 1.0
 - Added ability to use AVX when running TwoSpect
 - Better error handling for vectormath functions
 - Combine the sse/avx integration in cdfwchi2 to be a single 'fast' function
 - Change templateSearch_scox1Style output to be passed by reference