Allow upload of txt and md files

And fix the double comma while we are here anyway.

application/config/config-defaults.php

@@ -82,7 +82,7 @@
 $config['userideditable']     =  'N';               // Allow editing of user IDs
 $config['defaulttemplate']    =  'default';         // This setting specifys the default theme used for the 'public list' of surveys
 
-$config['allowedtemplateuploads'] = 'gif,ico,jpg,png,css,js,,map,json,eot,svg,ttf,woff';  // File types allowed to be uploaded in the templates section.
+$config['allowedtemplateuploads'] = 'gif,ico,jpg,png,css,js,map,json,eot,svg,ttf,woff,txt,md';  // File types allowed to be uploaded in the templates section.
 
 $config['allowedresourcesuploads'] = '7z,aiff,asf,avi,bmp,csv,doc,docx,fla,flv,gif,gz,gzip,ico,jpeg,jpg,mid,mov,mp3,mp4,mpc,mpeg,mpg,ods,odt,pdf,png,ppt,pxd,qt,ram,rar,rm,rmi,rmvb,rtf,sdc,sitd,swf,sxc,sxw,tar,tgz,tif,tiff,txt,vsd,wav,wma,wmv,xls,xlsx,xml,zip,pstpl,css,js';   // File types allowed to be uploaded in the resources sections, and with the HTML Editor