detectRequestUri uses improved isSSLConnection

- `detectRequestUri` uses `isSSLConnection` instead of own - duplicated code.
- `isSSLConnection` has been improved:
  - concatenated `isset` and `!empty` checks into one (see: php.net: [empty](http://us1.php.net/empty), [$_SERVER['HTTPS']](http://www.php.net/manual/en/reserved.variables.server.php))
  - no more checks for `getenv('SSL_PROTOCOL_VERSION')`, this variable has been renamed to [`SSL_VERSION`](http://httpd.apache.org/docs/trunk/da/ssl/ssl_compat.html) anyway
  - for IIS the value is compared against lowercase off: `strtolower($_SERVER['HTTPS']) != 'off'`

See discussion on #213