Enable separated control element

Adds the option to create the loading control disconnected from the zoom
control. This enables greater freedom in styling the indicator,
including 22px sq. working area (as opposed to 16px sq. when attached to
the zoom control).
Merge branch 'master' into codefox421-detatched-indicator
Merge branch 'master' into codefox421-detatched-indicator

Conflicts:
	src/Control.Loading.js
Comments line-length
Simplify container creation on `separate: true`

It doesn't currently make sense to think about a separate loading control when
there is no zoom control to be separate from.