change config_error to std::runtime_error in scale_hsla struct
Merge pull request #2610 from kernelsanders/master

change config_error to std::runtime_error in scale_hsla struct
micro-optimization to avoid recreating ellipse
no need for image filter
no need for rx/ry
consistent std::move in image data move ctor
Merge branch 'master' of github.com:mapnik/mapnik into dots