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

Keep only std::map<std::string, std::string> initializer list.
Corrected examples. 

Python bindings running but not printing values with bpls. Min and Max
captured correctly.

IO SetParameters and AddTransport will accept vector and map

Variable.cpp and Variable.tcc for complete separation of core components
in the public include

bool flag checks are implicit
Removed single letter enums in ADIOSTypes.h
All enums are enum class in ADIOSTypes.h using CamelCase
ADIOS uses delegating constructor
Using return type of emplace for IO (in ADIOS) and Variable (in IO)
Removed all base class include from inl template file

- Added examples/groupless/multistep writer example to the build
- Added ADIOS1 reader but it does not work yet
- Added heat transfer example reader

mpi and nompi:

helloBPWriter
timeBPWriter

Fix Variable.SetSelection(). heatTransfer adios2 writer is intentionally broken to keep to the intended API.