Create video/bliptv mimetype

Just like #1823078: Create video/vimeo mimetype and #1812976: Register video/youtube mimetype and provide an upgrade path this module needs to register a video/bliptv mimetype and associate it with video files. This is required to work with the new media module.

It should look something like this:

/**
 * Implements hook_file_mimetype_mapping_alter().
 */
function media_bliptv_file_mimetype_mapping_alter(&$mapping) {
  $mapping['mimetypes'][] = 'video/bliptv';
}

/*
 * Implements hook_file_default_types_alter().
 *
 * Adds the video/bliptv fake mimetype to video files.
 */
function media_bliptv_file_default_types_alter(&$types) {
  $types['video']->mimetypes[] = 'video/bliptv';
}

But it should also probably be automatically enabled when blip.tv is checked off as an allowed stream type. (right now you have to put video/bliptv in the mimetype textarea)