Use a 2-pass approach to generate ADIOS2.config.  The first pass
generates the configurable options in the header and the second pass
configures them.  This allows for consistency in the options used and
thier ordering with respect to where they're used elsewhere.

Subroutine based, calls the C bindings using opaque pointers
Working helloBPWriter_f in MPI and nonMPI examples
Separated MPI and nonMPI interfaces in Fortran and C
Passing character array by trimming and adding char(0) null terminated

To do:
Add testing

Builds libadios2_c.a and libadios2_c.so 
Verified with and without MPI
Added nonMPI hello bp write example
Added new ADIOS2_USE_C ON/OFF cmake argument

To do:
Add C tests and cmake support for the latter

Wrapper classes CompressBZip2 and CompressZfp implemented
Under transform/compress and adding examples and tests
Added/Modified cmake files
Makign changes to cmake from PR review

To do:
Add more tests

* Add initial python support to CMake build

* pybind11 2017-04-07 (1df91d36)

Code extracted from:

    https://github.com/pybind/pybind11.git

at commit 1df91d36cfa997c8987889234304ea5e37cc3e68 (v2.1.1).

* Build python bindings with cmake

* Adjust for adios2py -> adios2 module name