Send-get/get_with_offset_1d.f90: Needs sync all at the end of the main program

	or the scope where array descriptors are stored may be already
	destroyed when accessed by other (slower) images.
mpi_caf.c: Fixing sync_images, when a stopped image is slow to reach its
	caf_finalize and set the stopped status, while other images have read an
	ok status already and now wait on its send. Realized by using waitany
	and propagating a stopped image status.
	Small speed up in get_by_ref and smaller memory footprint.

Still failing tests:
hello_multiverse: This test fails in general with the gcc-7 fortran compiler,
	because the string is not composed correctly. This is independent
	of coarrays being present or not.

Author: vehre