empty-bin command options (recursive and liquid)

[foxxelias]

Added the -r | --recursive option to allow containers to be emptied on the floor recursively.

Added the -l | --liquid option and changed the basic behavior of the empty-bin command, to move items with the types LIQUID_MISC and DRINK to the floor you must explicitly specify option -l | --liquid

Example usage:
Select stockpile with bin, with filled waterskin inside and use empty-bin -l -r
This will recursively empty all containers on the stockpile, draining them of liquid if there is any in them.

*pictures*

[myk002]

apologies for updating the branch with a master merge -- I clicked the wrong button.

[myk002]

on another note, please feel free to add your name to https://github.com/DFHack/dfhack/blob/develop/docs/about/Authors.rst