Fix errors in README

and remove non-existent directory $(EX_DIR)/scripts from EXTRA_DIST in
Makefile.am
Auto detect scale-invariance and symmetry

- Automatically determine symmetry relations (source and target
  permutations; and +1/-1 scaling) for a kernel, for each symmetry type.

- Automatically determine if a kernel is scale-invariant or not.
  Determine the scaling factors for the source-density and
  target-potential.

- Include scaling for precomputed matrices (for scale-invariant kernels)
  in the row and column permutations. Add Scaling to enum Perm_Type; and
  compute and store permutations for all levels.

- Change Chebyshev quadrature in quad_rule to the analytical expression
  for weights, instead of computing weights through numerical
  integration.

- Declare quad_rule in include/cheb_utils.hpp.

- Implement log for QuadReal_t.

- Add SVD function to Matrix class.

- Restore original std::cout.flags() after printing Matrix or Vector.

- Store const-pointer to Kernel object in FMM_Pts (and FMM_Cheb) instead
  of a copy of the object.

- Change Chebyshev tree function-pointer declaration:
    -void fn_input(double* coord, int n, double* out)
    +void fn_input(const double* coord, int n, double* out)

- Make result tables wider (scripts/.results.sh).