Add simulation-specific configuration library

This branch adds config library for isolating simulation-specific code, and moves Truchas-specific code to a config::Truchas class. This branch also removes the "(Preview)" text from the Project menu label, and applies clang-format-3.8 to the source.

It is anticipated that the new config library will be eventually be replaced with simulation-specific python operators, so that compiled code specific for each simulation is not required.