Simplify zoom, fix in FF.

Simplify zoom, fix in FF.

- Greatly simplify zoom behavior with mousewheel by relying on work that D3 already does in regards to pan/zoom.
- Mousewheel zoom now works in firefox - differing event types from webkit weren't being handled in our code.
- Get rid of magic numbers for min/max values.

https://code.launchpad.net/~makyo/juju-gui/fffff-mousewheel/+merge/160970

(do not edit description out of merge proposal)

[matthew.scott, 2013-04-25 17:56:49]

Please take a look.

[gary.poster, 2013-04-25 18:09:24]

LGTM!

I can verify that (1) it WFM in Chrome, FF, and IE 10; and (2) it looks a lot
simpler!  Sadly, I'm not quite sure what you did, but +1 anyway. :-P

Great, thank you!

Gary

[jeff.pihach, 2013-04-25 20:16:13]

LGTM - Thanks a lot for this fix!

https://codereview.appspot.com/8961044/diff/1/app/views/topology/panzoom.js
File app/views/topology/panzoom.js (right):

https://codereview.appspot.com/8961044/diff/1/app/views/topology/panzoom.js#n...
app/views/topology/panzoom.js:99: if (!this.slider) {
you're reassigning so might as well use it :) 
if (!slider)

[matthew.scott, 2013-04-25 20:50:41]

*** Submitted:

Simplify zoom, fix in FF.

- Greatly simplify zoom behavior with mousewheel by relying on work that D3
already does in regards to pan/zoom.
- Mousewheel zoom now works in firefox - differing event types from webkit
weren't being handled in our code.
- Get rid of magic numbers for min/max values.

R=gary.poster, jeff.pihach
CC=
https://codereview.appspot.com/8961044