Add use strict to the places missing it

ci/makeMockCompiler.js

+'use strict'
+
 var fs = require('fs')
 var solc = require('solc/wrapper')
 var soljson = require('../soljson')

ci/sauceDisconnect.js

+'use strict'
+
 const https = require('https')
 
 var userName = process.argv[2]

src/app/example-contracts.js

+'use strict'
+
 var ballot = `pragma solidity ^0.4.0
 contract Ballot {
 

test-browser/helpers/contracts.js

+'use strict'
+
 module.exports = {
   checkCompiledContracts: function (browser, compiled, callback) {
     browser.execute(function () {

test-browser/mockcompiler/compiler.js

+'use strict'
+
 var Module = { // eslint-disable-line
   cwrap: function () { return arguments[0] === 'version' ? version : compile },
   writeStringToMemory: function () {},

test-browser/mockcompiler/requests.js

+'use strict'
+
 module.exports = {
   'testSimpleContract': {
     'sources': {

test-browser/tests/ballot.js

 'use strict'
+
 var testData = require('../mockcompiler/requests')
 // var contractHelper = require('../helpers/contracts')
 

test-browser/tests/simpleContract.js

 'use strict'
+
 var testData = require('../mockcompiler/requests')
 var contractHelper = require('../helpers/contracts')