Move redrawing out of operator implementations
Move redrawing out of operator implementations

Note that currently all windows are redrawn, this could be
further optimized to only redraw the affected windows.

8l/vis,trengrj/vis,clehner/vis,clehner/vis,twinshadow/vis,cpehle/vis,twinshadow/vis,rychipman/vis,rychipman/vis,8l/vis,trengrj/vis,cpehle/vis