ps 1.7.0

• ps now compiles on platforms that enable OpenMP (#109).

• New functions ps_get_cpu_affinity() and ps_set_cpu_affinity() to query
  and set CPU affinity (#123).

• ps_memory_info() now does not mix up rss and vms on Linux.

• ps_memory_info() now reports memory in bytes instead of pages on Linux (#115)