Merge branch 'release-4-6'

Merge branch 'release-4-6'

Conflicts:
	src/contrib/fftw/CMakeLists.txt
Resolved by merging bump to 3.3.3 and increased variable indirection
from both branches

	src/gromacs/legacyheaders/nbnxn_cuda_data_mgmt.h
Resolved with master - both branches have now removed fplog parameter
from the free function

	src/gromacs/legacyheaders/sim_util.h
	src/gromacs/mdlib/minimize.c
	src/gromacs/mdlib/tpi.c
	src/programs/mdrun/md.c
These are text clashes between master branch runtime ->
walltime_accounting encapsulation transition, and the recently merged
release-4-6 consolidation of start-time printing. There's no code
clash, though. Resolved by using the code that works consistent with
both refactorings. The call to the print_start function has to follow
the call to the walltime_accounting_start function, of course.

Change-Id: I1559fbadfc15eb7b7e880b17e4519159ba9b534e