Removed some old debug printfs
Made the old interposer tests work again

After Fredriks changes to the interposer the MPI_Datatype handles we
return from the (interposed) MPI_Type_create_* functions are no longer
valid MPI_Datatypes for other functions. Therefore we can not feed those
to functions like PMPI_Send. I fixed this by creating each dataype
twice, once with the interposed MPI functions and once with PMPI.
New Makefile, links against the interposer lib
Merge branch 'master' of https://github.com/fredrikbk/libpack