Added foundation-implementation to umbrella file, updated FLTObject t…

…o use super init, not self init (#17)

ios/Classes/FLTFoundationImplementation.m

@@ -28,7 +28,7 @@ - (instancetype)initWithBinaryMessenger:(id<FlutterBinaryMessenger>)binaryMessen
 @implementation FLTObject
 - (instancetype)initWithBinaryMessenger:(id<FlutterBinaryMessenger>)binaryMessenger
                         instanceManager:(FLTInstanceManager *)instanceManager {
-  self = [self init];
+  self = [super init];
   if (self) {
     _objectApi = [[FLTObjectFlutterApiImpl alloc] initWithBinaryMessenger:binaryMessenger
                                                           instanceManager:instanceManager];

ios/Classes/FLTInstanceManager-umbrella.h

@@ -6,3 +6,5 @@
 
 #import "FlutterInstanceManagerPlugin.h"
 #import "FLTInstanceManager.h"
+#import "FLTFoundationImplementation.h"
+#import "foundation.pigeon.h"