ShengBTE v1.5.0 released

Version v1.5.0 of ShengBTE has been released and can be obtained from the Downloads section. This version contains further contributions from Ben Durham focused on optimization, OpenMP parallelism and better reporting of progress. Details can be found at

https://bitbucket.org/sousaw/shengbte/pull-requests/9

It also includes a patch by Martí Raya Moreno to properly include the two-phonon matrix elements in the iterative procedure.