Bug fix in Collective metadata serialization using threads
Added more API functions in Python bindings

InquireVariable/Attribute working for valid name, but returning invalid
type

ADIOS constructor now has host language so bindings can change define
this at the constructor level

Separated C bindings from C glue (added) for languages using C-API (e.g.
Fortran)

Removed stl containers that pybind11 takes care of

BPWrite_c -> ctypes
XMLConfigTest.TwoIOs -> Test BP Writer 1

BP3 Deserialization:
Getting subfile seeks and intersection info
Set host language in bindings for row-major and zero-index info

Passed ctest (MPI and nonMPI) excluding ADIOS1 engine, and Python bindings
HDF5, C bindings and C++ tests working
Introduced BeginStep EndStep functions
Renamed IO GetVariable/Attribute to InquireVariable/Attribute

Getting and defining available Variables at Open
Storing Variable position in Metadata, added to VariableBase
mpidummy: Added support for MPI_Reduce, MPI_Gatherv
Added utils and BPLS

Implemented basic buffer reading functionality
Added threading for bp serialization/deserialization
Refactored MPI functionality
Engine is now a reference
Initial Read API

Testing and Examples issues after merging with master for conflicts
Fixing non-MPI issue
C enums and Fortran parameters now compatible

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

Added GetVariableBase* in IO needed by C bindings and real-time
applications, nullptr is a valid state in return.

Added c bindings test under testing/adios2/bindings/c
Updating ReadMe.md to include ADIOS2_USE_C for C bindings

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

Added working example examples/hello/bpWriter/helloBPWriter.c
Changed Engine signature to resolve Write void* at runtime (required by
C bindings).

To do:
CMake infrastructure
Testing

Makefile compiles

To do:
CMake infrastructure
Verify struct adios2_Engine  forward declaration
Add tests

Copy constructor was implicitly removed for ADIOSPy due to m_ADIOS.

PyBind11 needed the copy constructor.

m_ADIOS is now a shared pointer to avoid copy constructor removal

Separated MPI nonMPI test as ctest failed for MPI

Fixes #196

Fixes #197

Fixes #153

Fixes #193

Verified MPI and sequencial version

Removed IO Open that takes a new communicator (didn't work)