meta-json: Add initial test subgraph

operations/json/dropshadow2.fbp

+INPORT=translate.X:X
+INPORT=translate.Y:X
+INPORT=color.VALUE:COLOR
+INPORT=blur.STD_DEV_X:RADIUS
+INPORT=input.OUTPUT:INPUT
+OUTPORT=over.OUTPUT:OUTPUT
+
+# FIXME: multiple export mapping? INPORT=blur.STD-DEV-Y:RADIUS
+# FIXME: allow - in property names, or map _ to - ?
+# TODO: allow \ or \n between connections
+
+input(gegl/noop) OUTPUT -> INPUT darken(gegl/src:in) OUTPUT -> INPUT blur(gegl/gaussian:blur) OUTPUT -> INPUT opacity(gegl/opacity) OUTPUT -> INPUT translate(gegl/translate) OUTPUT -> INPUT over(gegl/over)
+input OUTPUT -> AUX over
+color OUTPUT -> AUX darken
+
+'rgb(0.0,0.0,0.0)' -> VALUE color

operations/json/dropshadow2.json

+{
+  "processes": {
+    "input": {
+      "component": "gegl/noop"
+    },
+    "darken": {
+      "component": "gegl/src",
+      "metadata": {
+        "routes": "in"
+      }
+    },
+    "blur": {
+      "component": "gegl/gaussian",
+      "metadata": {
+        "routes": "blur"
+      }
+    },
+    "opacity": {
+      "component": "gegl/opacity"
+    },
+    "translate": {
+      "component": "gegl/translate"
+    },
+    "over": {
+      "component": "gegl/over"
+    }
+  },
+  "connections": [
+    {
+      "src": {
+        "process": "input",
+        "port": "output"
+      },
+      "tgt": {
+        "process": "darken",
+        "port": "input"
+      }
+    },
+    {
+      "src": {
+        "process": "darken",
+        "port": "output"
+      },
+      "tgt": {
+        "process": "blur",
+        "port": "input"
+      }
+    },
+    {
+      "src": {
+        "process": "blur",
+        "port": "output"
+      },
+      "tgt": {
+        "process": "opacity",
+        "port": "input"
+      }
+    },
+    {
+      "src": {
+        "process": "opacity",
+        "port": "output"
+      },
+      "tgt": {
+        "process": "translate",
+        "port": "input"
+      }
+    },
+    {
+      "src": {
+        "process": "translate",
+        "port": "output"
+      },
+      "tgt": {
+        "process": "over",
+        "port": "input"
+      }
+    },
+    {
+      "src": {
+        "process": "input",
+        "port": "output"
+      },
+      "tgt": {
+        "process": "over",
+        "port": "aux"
+      }
+    },
+    {
+      "src": {
+        "process": "color",
+        "port": "output"
+      },
+      "tgt": {
+        "process": "darken",
+        "port": "aux"
+      }
+    },
+    {
+      "data": "rgb(0.0,0.0,0.0)",
+      "tgt": {
+        "process": "color",
+        "port": "value"
+      }
+    }
+  ],
+  "inports": {
+    "x": {
+      "process": "translate",
+      "port": "y"
+    },
+    "color": {
+      "process": "color",
+      "port": "value"
+    },
+    "radius": {
+      "process": "blur",
+      "port": "std_dev_x"
+    },
+    "input": {
+      "process": "input",
+      "port": "output"
+    }
+  },
+  "outports": {
+    "output": {
+      "process": "over",
+      "port": "output"
+    }
+  }
+}