Reverts a default behaviour that was changed in a previous commit.

[This commit](https://github.com/dan-coulter/phpflickr/commit/fe6f493de1aabe0a34d50fa7bab489494716942f#diff-9b9a87a6f1636876e0a3987693811e9cR319) changed the default behaviour of the `request()` function to *not* clean text nodes as they come in, resulting in drastic structural changes to almost all data coming back from Flickr.

This update reverts the code back to the original behaviour (but still with mikeMTOL's improvements) so it will not break any apps that have already been using phpFlickr and decide to update.