prepare for v.4.2

gui.js

@@ -3502,7 +3502,7 @@ IDE_Morph.prototype.aboutSnap = function () {
         module, btn1, btn2, btn3, btn4, licenseBtn, translatorsBtn,
         world = this.world();
 
-    aboutTxt = 'Snap! 4.1.3 - dev -\nBuild Your Own Blocks\n\n'
+    aboutTxt = 'Snap! 4.2 - dev -\nBuild Your Own Blocks\n\n'
         + 'Copyright \u24B8 2018 Jens M\u00F6nig and '
         + 'Brian Harvey\n'
         + 'jens@moenig.org, bh@cs.berkeley.edu\n\n'