Named INPUT_FLAG_1 to INPUT_FLAG_DROPDOWN_STAY_OPEN
Named INPUT_FLAG_2 to INPUT_FLAG_DROPDOWN_MOUSE_UP
placed RCT2_ADDRESS_INPUT_FLAGS where valid and replaced all bitwise
references to it with appropriate input flags.
Changed ride view dropdown to hold only as it should be.
- Rename var_146 to fair_value (it is not reliability)
- Add a helper method get_age_penalty which computes the age penalty for
a ride.
- Adds a constant for a ride's initial reliability
- Names a subroutine