Added ability to set draw range
Merge branch 'master' into drawrange
Changed TileLayer:clear with merge
Added new draw parameters (ox,oy) and changed behavior of (x,y):

The (ox,oy) parameters accept origin offsets and are affected by parallax.
The (x,y) parameters now only affect the location to draw the map.
Changed: Map now have new properties (x,y,ox,oy)
Removed: draw parameters
Added Map:autoDrawRange
Added limit test to not check tiles out of range
Some notes added
Removed Map:stagToIso/isoToStag
Changed: TileLayer:isoRectangle code refactored (much faster!)
Slight staggered loop tweak
Merge opacity fix
Fixed objectlayer not applying parallax
Merge branch 'master' into drawrange
Changed Map:setDrawRange to not always redraw:

Check if the new draw range doesn't share the same cells as the prev
cells; if it does, skip redrawing.
Changed map.drawrange to map._drawrange (Private!)
Assign parent to arg table when using map/objectlayer constructor
Changed loader to include traceback when returning error msg
Fixed incorrect empty field: _drawrange
Added support for objectlayer to only draw objects in view
Added Object:drawAABB/updateAABB
Change default parallax values to 0 for layers
Removed Object:drawAABB