[R] dataimport: refine error detection Consider only None as non-expected value after parsing the input file. False is now allowed because of the boolean yesno checker that returns False by default.

\.svn
^build$
^dist$
\.pyc$
\.pyo$
\.bak$
\.old$
\~$
\#.*?\#$
\.swp$
^doc/book/en/apidoc$