Use pre-compiled regex in dataFilter.
Fixed: Pagebreak becomes editable when pasting.
Used data-cke-display-name attribute instead of an invalid reference to element#classes to distinguish pasted pagebreak.
Use data-cke-pagebreak to distinguish pasted pagebreak.
Made pagebreak command and dataFilter re-use the same set of attributes to ensure the internal coherence.
Manually compresed pagebreak's CSS.
Removed IE6's CSS rule.