Remove hardcoded numeric deltas from hook_filter_info()

Remove the concept of numeric deltas and use unique filters' names to declare and identify filters. Instead of using hardcoded numeric deltas and $module/$delta pairs to reference filters, an unique name, namespaced in the module that provides the filter should be used.

See #216072: DROP Task: Remove hardcoded numeric deltas from all hook_block() implementations in core for reference.

Example:

function filter_filter_info() {
  $filters['filter_html'] = array(
    'name' => t('Limit allowed HTML tags'),
    'description' => t('Allows you to restrict the HTML tags the user can use. It will also remove harmful content such as JavaScript events, JavaScript URLs and CSS styles from those tags that are not removed.'),
    'process callback' => '_filter_html',
    'settings callback' => '_filter_html_settings',
    'tips callback'  => '_filter_html_tips'
  );
  $filters['filter_autop'] = array(
    'name' => t('Convert line breaks'),
    'description' => t('Converts line breaks into HTML (i.e. <br> and <p>) tags.'),
    'process callback' => '_filter_autop',
    'tips callback' => '_filter_autop_tips'
  );
  $filters['filter_url'] = array(
    'name' => t('Convert URLs into links'),
    'description' => t('Turns web and e-mail addresses into clickable links.'),
    'process callback' => '_filter_url',
    'settings callback' => '_filter_url_settings',
    'tips callback' => '_filter_url_tips'
  );
  $filters['filter_htmlcorrector'] = array(
    'name' =>  t('Correct broken HTML'),
    'description' => t('Corrects faulty and chopped off HTML in postings.'),
    'process callback' => '_filter_htmlcorrector',
  );
  $filters['filter_html_escape'] = array(
    'name' => t('Escape all HTML'),
    'description' => t('Escapes all HTML tags, so they will be visible instead of being effective.'),
    'process callback' => '_filter_html_escape',
    'tips callback' => '_filter_html_escape_tips'
  );
  return $filters;
}

Postponed as it is dependent of #546336: hook_filter_info(): Remove $op from hook_filter()