Interactive diff-merge with vimdiff

Implement a interactive mode for merging bug contents with ``vimdiff`` or ``gvimdiff``.

[g]vimdiff has the ability to diff an arbitrary number of files side by side.

Possibly not only the bug's long text could be merged, but all writable bug attributes. The bug's state would be represented in text form, special headings would identify each attribute. The program would search for these headings in the text representing the merged bug. It would be very beneficial for this idea, if individual lines could be write protected in Vim.