Add double[] support

src/NetworkTables/NT4Client.swift

@@ -193,6 +193,8 @@ class NT4Client: WebSocketDelegate {
             }
             // If the topic is not found, return
             guard let topic = topic else { return }
+            topic.latestValue = data
+            topic.latestTimestamp = timestamp
             onNewTopicData?(topic, timestamp, data)
         } else if topicID == -1 {
             // Handle receive timestamp

src/NetworkTables/NTStructures.swift

@@ -73,6 +73,8 @@ class NTTopic {
     var name: String = ""
     var type: String = ""
     var properties: [String: Any] = [:]
+    var latestValue: Any? = nil
+    var latestTimestamp: Int64 = -1
 
     init(uid: Int, name: String, type: String, properties: [String: Any]) {
         self.uid = uid
@@ -129,4 +131,17 @@ class NTTopic {
             return 5 // Default to binary
         }
     }
+
+    func getDoubleArray() -> [Double]? {
+        if("double[]" != type) {
+            NSLog("Attempted to get double array from non-double[] topic")
+            return nil
+        }
+        if let val = latestValue as? [Double] {
+            return val
+        } else {
+            NSLog("Failed to cast latest value to double array")
+            return nil
+        }
+    }
 }