Fix 16 linter warnings in Examples/

Summary: Partially fixes #3316 by addressing 16 linter warnings:
 - Strings should be singlequote
 - Missing semicolon

Travis build jobs 1.1 through 1.4 complete successfully. 1.5 fails through what appears to be an unrelated issue on master.
Closes https://github.com/facebook/react-native/pull/3332

Reviewed By: @​svcscm

Differential Revision: D2531718

Pulled By: @javache

fb-gh-sync-id: ca22fbeac5fe3b4f725775a72f21b6dd7a75d94b

Libraries/JavaScriptAppEngine/Initialization/ExceptionsManager.js

@@ -114,7 +114,7 @@ function stackFrameToString(stackFrame, maxLength) {
   var fileName = fileNameParts[fileNameParts.length - 1];
 
   if (fileName.length > 18) {
-    fileName = fileName.substr(0, 17) + '\u2026' /* ... */;
+    fileName = fileName.substr(0, 17) + '\u2026'; /* ... */
   }
 
   var spaces = fillSpaces(maxLength - stackFrame.methodName.length);

Libraries/JavaScriptAppEngine/Initialization/loadSourceMap.js

@@ -48,7 +48,7 @@ function fetchSourceMap(): Promise {
       return Promise.resolve(url);
     })
     .then(fetch)
-    .then(response => response.text())
+    .then(response => response.text());
 }
 
 function extractSourceMapURL({url, text, fullSourceMappingURL}): ?string {