Adds podspec for RxLibrary and sample app

src/objective-c/examples/Sample/SampleTests/SampleTests.m

+//
+//  SampleTests.m
+//  SampleTests
+//
+//  Created by Jorge Canizalez Diaz on 2/16/15.
+//  Copyright (c) 2015 gRPC. All rights reserved.
+//
+
+#import <UIKit/UIKit.h>
+#import <XCTest/XCTest.h>
+
+@interface SampleTests : XCTestCase
+
+@end
+
+@implementation SampleTests
+
+- (void)setUp {
+    [super setUp];
+    // Put setup code here. This method is called before the invocation of each test method in the class.
+}
+
+- (void)tearDown {
+    // Put teardown code here. This method is called after the invocation of each test method in the class.
+    [super tearDown];
+}
+
+- (void)testExample {
+    // This is an example of a functional test case.
+    XCTAssert(YES, @"Pass");
+}
+
+- (void)testPerformanceExample {
+    // This is an example of a performance test case.
+    [self measureBlock:^{
+        // Put the code you want to measure the time of here.
+    }];
+}
+
+@end