Setting default securityLevel to strict, updated docs in mermaidAPI

gulpfile.js

@@ -1,19 +1,9 @@
 import gulp from 'gulp'
 import jison from 'gulp-jison'
 import print from 'gulp-print'
-// const es = require('event-stream')
-
-const logFile = function (es) {
-  return es.map(function (file, cb) {
-    log(file.path)
-    return cb()
-  })
-}
 
 gulp.task('jison', function () {
   return gulp.src('./src/**/*.jison')
-    // .pipe(filelog('Jison file:'))
-    // .pipe(logFile(es))
     .pipe(print())
     .pipe(jison({ 'token-stack': true }))
     .pipe(gulp.dest('./src/'))