Add options to push about slate

[jigish]

monitor is sort of useless and doesn't fit the idea of a "push". Adding style only. Workaround for monitor is to simply use a "move".

[jigish]

Added style option with the following values:

none - normal push
center - push to direction and center
bar - push to direction and resize to fill other direction ("push right bar" will push the window to the right and resize it to fit the height of the screen
bar-resize:expression - same as above but will also resize the distance away from pushed edge with "expression"

[supersonicclay]

In case anyone is looking for how to move to another screen and center, here's what I use:

bind right:ctrl;alt;cmd move screenOriginX+((screenSizeX-min({screenSizeX,windowSizeX}))/2);screenOriginY+((screenSizeY-min({screenSizeY,windowSizeY}))/2) min({screenSizeX,windowSizeX});min({screenSizeY,windowSizeY}) right
bind left:ctrl;alt;cmd  move screenOriginX+((screenSizeX-min({screenSizeX,windowSizeX}))/2);screenOriginY+((screenSizeY-min({screenSizeY,windowSizeY}))/2) min({screenSizeX,windowSizeX});min({screenSizeY,windowSizeY}) left
bind up:ctrl;alt;cmd    move screenOriginX+((screenSizeX-min({screenSizeX,windowSizeX}))/2);screenOriginY+((screenSizeY-min({screenSizeY,windowSizeY}))/2) min({screenSizeX,windowSizeX});min({screenSizeY,windowSizeY}) up
bind down:ctrl;alt;cmd  move screenOriginX+((screenSizeX-min({screenSizeX,windowSizeX}))/2);screenOriginY+((screenSizeY-min({screenSizeY,windowSizeY}))/2) min({screenSizeX,windowSizeX});min({screenSizeY,windowSizeY}) down