Issue #78 Legacy Api
Creating a single DateTime object representing the time of the shows
Changes in response to Peter's suggestions:

- Using showdata.php as the route
- Passing the router into ApiShow instead of the controller
- Moving to single route rather than 2
- Removing stray 'use Illuminate\Routing\UrlGenerator'
Adds list of admins and pending admins to the "admin panel" for shows. Work done as part of #76.

The next step is to allow editing of these lists and ideally in an intuitive way.
Resolves #84. Addition break in layout.html.twig improves the layout of panels.
Merge pull request #81 from stumo/legacyapi

Merged Stumo's legacyapi work into master
Initial work on 'Shows' page #31
Made a 'show admin' page, which includes shows a user 'owns' and unauthorised shows for admins #31
Made 'unauthorised shows' section appear for society/venue admins too, along with shows they can authorise #31
Made 'Authorise this show' button actually do something #31
Tweaked show admin panel
Replaced <br> with a bit of padding
Removed 'shows' linked adding unintentionally #31
Changed voters to use strpos instead of strict equality so that they accept Doctine proxy objects. Was preventing roles from updating because $role->getShow() returns a proxy #54
Added 'audextra' field to auditions page and created auditions diary view
Made statistics include distinct count of venue names where 'venue' is not set #61
Fixed performances query. Now reads '1 performance of 1 show' for the week in question. Also created 'plural' Twig function #53
Fixed bug in AuthenticationSuccessHandler
Changed image bundle to use pure HTML5 file uploading (with HTML4) backup #37
Reviewed positioning of image on show, society and venue pages #37