Make checkIsMyInvitation use Django to parse the URL
Using django is more reliable and makes the code easier to read as
there is no knowledge of the url layout required.
Patch by: Sverre Rabbelier
input.field, select.field {width:200px;}
input.picker {width:179px; margin-left: 5px;}
input.disabled {border-color:#F2F2F2;}
img.picker {vertical-align:text-bottom; cursor:pointer;}
h1 {padding: 0 0 5px 0;}
.panel_wrapper div.current {height:160px;}
#xhtmlxtrasdel .panel_wrapper div.current, #xhtmlxtrasins .panel_wrapper div.current {height: 230px;}
a.browse span {display:block; width:20px; height:20px; background:url('../../../themes/advanced/img/icons.gif') -140px -20px;}
#datetime {width:180px;}