- Fix URL (old link dead)

- Update to version 0.922:
* In the table class, the set() function no longer automatically
adds rows or columns. This prevents some behavior which was
not intuitive for users.
* Several tensor functions have been added, including
tensor::swap_data(), tensor_out(), tensor::min(),
tensor::max(), tensor::copy(), tensor::is_valid().
* Slicing for tensor_grid objects has been improved.
* Copy constructors for tensor and tensor_grid have been
created.
* A few long double integration classes have been added when
higher accuracy is required.
* The MCMC classes have been completely reworked, offering
better support for OpenMP and MPI parallelism.
* The acol command has been expanded and improved in several
ways. Code for o2graph has been moved out and the
documentation has been improved.
* The conversion functions in convert_units now has a const
version
* The documentation has been improved everywhere.
* A new nearest neighbor interpolation type has been added.
* A seed bug in rng_gsl has been fixed.
* HDF5 I/0 for table3d types now allows const references.
* The cloud_file class is updated and simplified.
* The prob_dens_func_amr class has been updated.
* Some work has been done on heat capacity functions for
particle objects.
* The fermion_rel::calc_mu() and pair_mu() functions work better