Add dropping of objects in inventory

[picosonic]

Add putting down of objects when ENTER pressed

[picosonic]

When not over another object, show inventory, give player option to select object to drop or leave inventory with no change

Note: Part of this routine is used when making space for object cycling when bag is full

[picosonic]

Just realised I’ve only done enough of this to slow pick-up to work. So more to do to select what to drop or use.