Replace the old link to the science paper by one on archive-mozilla
website. Remove the original source link as I can't find any archived
version of it (even on archive.org, only the folder structure is saved,
not actual files themselves, so it's useless).

Also add some history, which is probably a nice touch.

Add a link to crossroad to help people who'd want to cross-compile
uchardet.

Finally add the R binding by Artem Klevtsov and QtAV as reported.