Got the installer working. Fixed a few bugs including a nasty-to-debug issue where the lang_id was being hardcoded during installation, resulting in strings being inserted with the wrong lang_id causing an infinfinite loop with fetch() throwing a "no strings" error and using template (which calls fetch()) to complain
(function(){tinymce.create('tinymce.plugins.AutoSavePlugin',{init:function(ed,url){var t=this;t.editor=ed;window.onbeforeunload=tinymce.plugins.AutoSavePlugin._beforeUnloadHandler;},getInfo:function(){return{longname:'Auto save',author:'Moxiecode Systems AB',authorurl:'http://tinymce.moxiecode.com',infourl:'http://wiki.moxiecode.com/index.php/TinyMCE:Plugins/autosave',version:tinymce.majorVersion+"."+tinymce.minorVersion};},'static':{_beforeUnloadHandler:function(){var msg;tinymce.each(tinyMCE.editors,function(ed){if(ed.getParam("fullscreen_is_enabled"))return;if(ed.isDirty()){msg=ed.getLang("autosave.unload_msg");return false;}});return msg;}}});tinymce.PluginManager.add('autosave',tinymce.plugins.AutoSavePlugin);})();