Update to support new version of js.tinymce

Updates to javascript file to comply with new TinyMCE api. activeEditor.windowManager is used instead of tinyMCEPopup which is now deprecated.
Some plugins names are changed and options on TinyMCE, so the code is changed to support those.
Usage of RichTextWidget in Kotti can stay the same, but now there is only one theme ("modern") instead of "simple" and "advanced" that were there before, but if the options are used the theme will fallback to the new default one.

I also removed coffescript file, because i made changes to javascript directly.