default all pan/zoom/resize options to "the good one"

[gordonwoodhull]

Now that we worked out how to detect size changes in the parent div and reset the scales appropriately, this feels like the right combination which almost everyone will want most of the time:

• width/height 'auto' - yes it's tricky but it seems to be working. I have applied it in all the demos and a couple of other places
• restrictPan true - when does the user want to be able to pan everything off the screen? the only issue here is it jerks back and forth a little right where the canvas gets to the same size as the div, maybe there could be a little tolerance
• a higher-level fitStrategy higher-level zoom features #101

Features which seem so simple until you really look at them...