The tool is in python so stick it in a maya python folder. For the maya hotkeys you will need to set 2 commands, one for when your key is pressed, and one for when you release the key. This has to be the same combination of keys for the pressed and release, just like the default maya version. If not then you wont get your previous tool set back automagically and the timeline snapping will stay off.
on press
import timeDragger as td
reload(td)
td.drag(True)
on release
import timeDragger as td
reload(td)
td.drag(False)
get the python file here;
Download timeDrag script
Script updated to be less dumb! thanks, https://github.com/Regnareb