[Rd] a couple Sweave buglets

[Hin-Tak Leung]

Just a couple of small bug-lets/stuffs in Sweave:

- It stripes off the two lines starting with @ (this is a verbatim section showing plink's start-up message):

=======================================

@----------------------------------------------------------@
|         PLINK!       |    v0.99p     |   17/Dec/2006     |
|----------------------------------------------------------|
|  (C) 2006 Shaun Purcell, GNU General Public License, v2  |
|----------------------------------------------------------|
|       http://pngu.mgh.harvard.edu/purcell/plink/         |
@----------------------------------------------------------@

========================================

- XeTeX definitely does not like having any \usepackage[whatever]{inputenc}
(it assumes inputs are always utf-8)


While both of these can be worked around - using \input{} for anything Sweave might mess with, and put a % in front of \userpackage[inputenc] (Sweave seems to read LaTeX comments as real; but that's probaby a mis-feature...); SWeave probably should not stripe @ without a starting <<>>= noweb marker.

Had a couple of discussion elsewhere - it seems that international stuff in LaTeX, XeTeX and/or LuaTeX are the main ones to use, but for most parts people still stick to regional encodings (e.g. iso 8859-11 for Thai) so dependences on inputenc is not really useful.

FWIW.