Made the non-JavaScript date selectors hidden while the JavaScript date selectors are being prepared

git-svn-id: http://svn.code.sf.net/p/mrbs/code/mrbs/trunk@2911 25f7e783-145e-4f2d-a9f8-dd7182bfe9c7
Stopped the header jumping around on page refresh as the datepicker is set up

git-svn-id: http://svn.code.sf.net/p/mrbs/code/mrbs/trunk@2912 25f7e783-145e-4f2d-a9f8-dd7182bfe9c7