Print a good detail message when a conflict occurs and ways to resolve it, #214.

lib/core/manager.js

@@ -186,6 +186,7 @@ Manager.prototype.prune = function () {
     this.dependencies = prune(this.getDeepDependencies());
   } catch (err) {
     this.emit('error', err);
+    this.emit('data', err.details);
     return false;
   }
   return true;