zComplexDrone.toFront(): .toFront() now layers according to O.layer, rather than simply applying .toFront() to all the parts.
zSwarmConstructor.layer(): Now layers children axes as well as drones.
zSwarmConstructor.constructor: Drones inherit layers from swarms by default.
Change in zp.flags to allow centre-aligned flags.
Change class and case which are reserve names to objClass and toCase.
Created new zGladwrap object, which sits on top of graphs to captures mouseevents.
Added zp.sCurveTo()
Added zSimpleDrone.getPointAtDec() to expose Raphael's .getPointAtLength().

Updated zLayout.zoom() to scale margins, which preserves aspect ratio on zoom.
Added innerBox option to zLayout.getRect()

Changed zComplexDrone so that toFront() works even when no layers are defined (i.e. Indiscriminately run .toFront() on all elements).

Added zSwarm.instantRedraw()

Signed-off-by: Keith Ng <keith@point.org.nz>