Computations now occupy their own nodes on the dependency graph

This mitigates most issues with properties having self-loops, 
particularly in cases like Strength where the value `strength` is used 
in the description of Strength

app/imports/api/engine/computation/buildComputation/linkCalculationDependencies.js

@@ -4,9 +4,13 @@ import { traverse } from '/imports/parser/resolve.js';
 export default function linkCalculationDependencies(dependencyGraph, prop, {propsById}){
   prop._computationDetails.calculations.forEach(calcObj => {
     // Store resolved ancestors
-    let memo = {
+    const memo = {
       // ancestors: {} //this gets added if there are resolved ancestors
     };
+    // Add this calculation to the dependency graph
+    const calcNodeId = `${prop._id}.${calcObj._key}`;
+    dependencyGraph.addNode(calcNodeId, calcObj);
+
     // Traverse the parsed calculation looking for variable names
     traverse(calcObj.parseNode, node => {
       // Skip nodes that aren't symbols or accessors
@@ -17,10 +21,15 @@ export default function linkCalculationDependencies(dependencyGraph, prop, {prop
           node.name.slice(1), memo, prop, propsById
         );
         if (!ancestorProp) return;
-        dependencyGraph.addLink(prop._id, ancestorProp._id, calcObj);
+        // Link the ancestor prop as a direct dependency
+        dependencyGraph.addLink(
+          calcNodeId, ancestorProp._id, 'ancestorReference'
+        );
       } else {
         // Link variable name references as variable dependencies
-        dependencyGraph.addLink(prop._id, node.name, calcObj);
+        dependencyGraph.addLink(
+          calcNodeId, node.name, 'variableReference'
+        );
       }
     });
     // Store the resolved ancestors in this calculation's local scope