remove backends

Author: chearon

binding.gyp

@@ -60,12 +60,7 @@
       'include_dirs': ["<!(node -p \"require('node-addon-api').include_dir\")"],
       'defines': [ 'NAPI_DISABLE_CPP_EXCEPTIONS', 'NODE_ADDON_API_ENABLE_MAYBE' ],
       'sources': [
-        'src/backend/Backend.cc',
-        'src/backend/ImageBackend.cc',
-        'src/backend/PdfBackend.cc',
-        'src/backend/SvgBackend.cc',
         'src/bmp/BMPParser.cc',
-        'src/Backends.cc',
         'src/Canvas.cc',
         'src/CanvasGradient.cc',
         'src/CanvasPattern.cc',