Bug 832155: Move SVGFEPointLightElement to its own file r=Ms2ger

--HG--
rename : content/svg/content/src/nsSVGFilters.cpp => content/svg/content/src/SVGFEPointLightElement.cpp
rename : content/svg/content/src/nsSVGFilters.cpp => content/svg/content/src/SVGFEPointLightElement.h
Bug 832155: Convert SVGFEPointLightElement to WebIDL r=Ms2ger