Use floating point instead of int for dragging windows

[Philipp-M]

Hey there, nice project.
Looks quite nice already(loliwm)
I was just playing around a little bit with it, and found an issue while moving a window. If moving the cursor slowly while dragging a window, it wont move(I think because delta values under 0 are cut to 0), also after moving a window a lot, the cursor seems to go other ways than the window, it kinda drifts away. My experience says, that it is a float to int typecast issue(had some similar issues playing with touch and android).

[Cloudef]

Good point. I already fixed similar issue with subpixel mouse movement.
I should do the same here as well.

(And yes, it is fixed point issue, since velocities from pointer are floating point)

Btw, unless you develop with wlc, open future issues in loliwm project.