Minor Update - v0.1.15a

Change Notes

• Added a pressure relief valve
• Flywheel is now much heavier (slightly unrealistic for this size of engine but makes the game easier to play)
• Audio when filling water is now smoother
• Removing water from the tank previously didn't account for energy loss correctly
• Made audio volume slightly quieter
• Dampened some harsh audio frequencies
• Renamed "throttle" to "throttle valve" and reversed number reading on information panel
• Engine no longer makes an abrupt noise when the program is started