Basic functionality for xdiag including minimal Julia wrapper
Basic functionality for three Hilbert space types, Spinhalf, tJ, and Electron, has been implemented. Features are:
- Algebra with and without permutation symmetries
- Parallelization with OpenMP and MPI
- CMake has been properly set up
- Iterative algorithms present, Lanczos, Arnoldi, time evolution
- A minimal Julia wrapper has been written
- The Julia wrapper compiles on several target 64bit systems using BinaryBuilder