libpression version 0.19.0

libpression version 0.19.0

Major Changes

• BREAKING CHANGE pressio_release is no longer a noop, and has new
  signature. The signature change was made to better support wrappers
  like swig. It has been changed from a noop to freeing the memory
  associated with a particular instance of the library. This allows
  users to create several handles for the library for error handling
  purposes.
• BREAKING CHANGE new API pressio_compressor_release now should be called on
  pressio_compressor* pointers when they are no longer needed.
  Internally it uses shared pointers, and depending on the
  implementation of the compressor it either returns a static copy of
  the shared pointer (i.e. SZ) for compressors where global memory is
  used to configure compressors, or a new shared pointer for each (i.e.
  ZFP). This allows compressors such as ZFP that may be used in a
  multi-threaded context to actually be used in that way.
• BREAKING CHANGE pressio_instance now actually returns a new instance
  each time it is called rather than a possibly shared instance
• The plugin registration system has been completely re-written to no
  longer require disparate edits to various files to introduce new
  plugins, instead, users create an instance of pressio_register to
  register to their type. This also allows non-library compressors to
  be introduced without recompiling libpressio.

Minor Changes

• MemoryChecks are now supported for test cases. Various memory leaks
  in test cases are now removed. Added a valgrind suppression file for
  the libgomp malloc that is never freed when valgrind can see it.
• pressio_get_compressor and pressio_new_metrics now correctly
  return a nullpointer when the lookup fails
• SWIG now passes input arrays as INPLACE_ARRAYs instead. This has a
  minor performance improvement.
• New C++ only integration test case was added.
• Several private APIs were removed as no longer required

Bug Fixes

• a few incorrectly documented functions were correctly documented