Advanced settings menu

[wgurecky]

Description

Provide a way to adjust reactivity coefficients, reactor volume, cross sections, rod worth curve, ect. in an advanced menu.
Additionally, add presets for RBMK and PWR.

Tasks

• Expose reactor parameters though a nice reactor physics interface.
• Create additional menu in GUI. Link gui buttons/boxes with the reactor physics interface.
• Create presets to set reactor parameters to pre-defined values.