Feature Improvements

Cleaned the window for creation of data files to make it more user-friendly.
Added smoke visibility variables for light-emitting and light-reflecting objects (see SFPE Handbook). These variables appear for fire simulations only.
Changed the under-relaxation factor for energy and species to match momentum as the previous implementation caused convergence issues for extremely light or extremely heavy gases.
Various in:Flux Cloud improvements.
Improved notifications when simulations are not added […]