Remove XML illegal characters from console messages

Fixes following bug:

    at XMLStringifier.module.exports.XMLStringifier.assertLegalChar
(/Users/marat/Dev/railways/node_modules/karma-junit-reporter/node_module
s/xmlbuilder/lib/XMLStringifier.js:150:15)
    at XMLStringifier.assertLegalChar
(/Users/marat/Dev/railways/node_modules/karma-junit-reporter/node_module
s/xmlbuilder/lib/XMLStringifier.js:4:61)
    at XMLStringifier.module.exports.XMLStringifier.cdata
(/Users/marat/Dev/railways/node_modules/karma-junit-reporter/node_module
s/xmlbuilder/lib/XMLStringifier.js:35:19)
    at new XMLCData
(/Users/marat/Dev/railways/node_modules/karma-junit-reporter/node_module
s/xmlbuilder/lib/XMLCData.js:19:34)
    at XMLElement.module.exports.XMLNode.cdata
(/Users/marat/Dev/railways/node_modules/karma-junit-reporter/node_module
s/xmlbuilder/lib/XMLNode.js:155:15)
    at XMLElement.module.exports.XMLNode.dat
(/Users/marat/Dev/railways/node_modules/karma-junit-reporter/node_module
s/xmlbuilder/lib/XMLNode.js:267:19)
    at onBrowserComplete
(/Users/marat/Dev/railways/node_modules/karma-junit-reporter/index.js:62
:29)
    at null.<anonymous>
(/Users/marat/Dev/railways/node_modules/karma/lib/events.js:15:22)
    at emit (events.js:117:20)
    at onComplete
(/Users/marat/Dev/railways/node_modules/karma/lib/browser.js:145:13)