Add and fix h1 headers

I made several changes:

 * Added an h1 header to Handler/JsLicence.hs. I did not
   include a <div .center-text> because its inclusion did
   not seem to affect the placement of the text

 * Fixed the deprecated <center> tag in templates/notifications.hamlet

 * Added a centering tag in templates/projects.hamletjHandler/JsLicence.hs

 * Added an h1 header with a centering tag in templates/tickets.hamlet

 * Added an h1 header with a centering tag in templates/who.hamlet

 * Added an h1 header with a centering tag in templates/wiki_pages.hamlet.hamlet
   A possible next step here might be to have each project's name
   generated dynamically, so it reads "ProjectName Index"