Why am I doing this? It want to run RUnit tests from within 
R CMD check
check and interactively.
Files produced are compared with expected files. 
Now R CMD check and interactive (and batch) runs of RUnit
give different encodings.
I don't know why, but they do. And this is a rather lousy fix. See the code
for details.
Rd_txt_RUnit(txt)A character vector.
The sanitized character vector.