add a user's details page
split the bootstrap css bundle out into a separate bundle
add the ability to edit a user's details
make the title size match the other pages
add the ability to delete users
extract the common styles into a separate file

Both the main site and the admin section share some styles. These are now in a common stylesheet.
add a margin to the page to stop the content disappearing behind the navbar
add the user's joined date to the details
Merge pull request #270 from adrianbanks/users-pages-in-admin-section

Fix #268 User pages in the admin section

Fixed the links and implemented:

 - viewing user details
 - editing of all user details
 - deleting a user