Added a vector version (computing an array of Wigner-3j symbols) that use the Fortran backend.

This release fixes some issues in the C++ implementation of the routines.

This version is now packaged as a library. It uses CMake as a build helper. It also fixes an issue that caused the evaluation of certain strings of symbols where the boundary values were exactly 0.

This is the first release of the wignerSymbols library. The library can be used to compute the Wigner 3j and 6j symbols, as well as the related Clebsch-Gordan coefficients.

The library contains a re-implementation of the algorithm described by Schulten and Gordon as well as the original Fortran implementation. Both can be accessed by the user.