Use old method to init ckeditor
Instead of using global JS-variables and ignoring serendipity[textarea]={$view}, this
approach actually uses the variable and therefore reinstates wysiwyg_init.tpl.

ckeditor_custom_config.js (Thx Ian!) is still respected, but the toolbar got restored to the old version. We need an easy way to remove _underline_, for example. It could be extended though.

This fixes #{107} somewhat, as serendipity_image_selector.php is useable now, but still with display errors (and without an upload widget). Probably still a good idea to copy the ML-eapproach of the normal textareas

This also works with htmlnuggets, without using spawnnugget from the core, instead wysiwyg_init.tpl gets reused in the plugin-config.

ckeditor_custom_plugin.js got emptied, the relevant code (which should only be the part that adds the plugins into the toolbar) should be integrated into wysiwyg_init.tpl).
serendipity_editor.js.tpl without core
To have this in the plugin api didn't look right. the fallback to default works this time, so this should be alright.