Add missing commands to Environment Box

[arnobaer]

Add following missing commands to HEPHY Environment Box driver and emulator:

• SET:CTRL ON|OFF and GET:CTRL ? for PID controller state (0=OFF, 1=ON)
• SET:PID_DOOR_STOP ON|OFF and GET:PID_DOOR_STOP ? for PID door open stop state (1=OFF, 2=ON) (sic!)

[arnobaer]

Fixed typos in commands:

• SET:PID_DROP_MODE M|E -> SET:PID_PROP_MODE M|E
• GET:PID_DROP_MODE ? -> GET:PID_PROP_MODE ?

Fixed typos in driver:

• pid_drop_mode -> pid_prop_mode in PC_DATA dict.