Improve RTF Import (RTF Tokenizer)

by Miklos Vajna for LibreOffice

For the ooxml Word import filter, a new filter framework is developed that has better import quality as the old separate filters, and also shares quite some code. Having the RTF import use that framework would be hugely useful; both binary doc and rtf are very similar in structure, and could have tokenizers plugged into the filter framework. The doc tokenizer is already worked on, so a RTF tokenizer would be a an awesome feature - and this summer I would like to work on this.