Create a boost PropertyTree generator

[mithro]

boost is a popular C++ library and has a sub-library called PropertyTrees. It would be good to have a generator which supports this system.

See the following links for more information,

• https://www.boost.org/doc/libs/1_65_1/doc/html/property_tree.html
• http://techgate.fr/boost-property-tree/
• https://theboostcpplibraries.com/boost.propertytree