paranumal/libparanumal: v0.5.0

Lots of new goodies! Now completely memory leak-free, and valgrind-clean!

• New comm_t object to encapsulate all MPI
• Error handling via std::exceptions
• New memory<T>, deviceMemory<T>, and pinnedMemory<T> types
  • Memory management objects, with shallow copy semantics and automatic garbage collection
  • memory<T> is essentially a thin wrapper of std::shared_ptr<T[]>
  • deviceMemory<T> and pinnedMemory<T> are thin wrappers of occa::memory
• New device-aware gather scatter functionality in ogs library, replacing gslib
• New ParAdogs library for distributed parallel mesh partitioning
• Device/Host Timers