vim/README:
Removed warning about ~/.vim/after/filetype.vim,
Add utf-8 encoding detection.
Added more details to the Vim README and
vim/after/filetype.vim:
vim/ftdetect/mercury.vim.
Renamed file type detection for Mercury to ftdetect/mercury.vim. This
allows one to install the vim configuration files with a single command:
$ cp -r vim/ ~/.vim
vim/syntax/mercury.vim:
Fixed escaping of the escape character in strings,
