Support for ADIOS compression

 - enable ADIOS zlib compression for 1.7.0+ and applicable datasets
 - set default ADIOS transport method to MPI_AGGREGATE
Make compression method selectable
Add cmd line flags for adios MPI

 - command line flags for MPI aggregators and OST
 - use 'none' as default data transform
Fix compile error (always create member)
Integrate review comments

 - change -D flag
 - set default num aggr. to mpi size
Merge pull request #494 from f-schmitt-zih/topic-adios1.7

Adios 1.7.0 support