lots and lots of changes
Persistent comms may be reused after a wait, do not put their handle to MPI_REQUEST_NULL
Clean surf code
Some cleanup in FindNS3.cmake.
generalize behavior of commit 3391e81 to other test/wait functions
Change the way persistent MPI_Request are handled after their use.
Don't change the address of the buffer of the MPI_Request for a send, as it may be reused.
get the doc in sync with what happens in code (thanks to Luke Berthot for the report)
obvious typo
ignore some more example binaries
hide some new advanced variables in CMake
Rename a test to clearly show that it should properly detect bogus input files
add a test reproducing the issue experienced by Luke Bertot
fix the dist target