Scale instances without waiting

[enrichman]

At the moment if you want to scale the instances of your application you need to wait for the previous scaling to be ready.

I.e: if I want to scale from 1 to 4 instances I need to scale to 2, wait, then 3, wait, then 4.

It will be nice to just press the plus button from 1 to 4, and then scale the instances.

(AK clarification: Basically defer the call to the app update API for a bit (1/10th of a second maybe, or 2/10th), and if the user keeps clicking on the buttons keep defering, until the click sequence stops. Then call the API.)

Or maybe we could also have an input field that could be edited manually (a bit dangerous?). I would prefer to have the same behavior with just the delay.

(AK clarification: This could make use of the same defered call to the API, i.e. waiting until the user has stopped typing. Or it could use a explicit commit button).

[richard-cox]

This is currently an improvement in #277, but is worthy of it's own issue