Make the scread can deal with the keyword.

Make the scread can deal with the
keyword, when you input the keyword
after the filename, the scread will
just output the ast node about the
keyword. It is judged by the ast
spelling.

If you just input the filename after
the scread, scread will output all the
ast node information, exception the first
node. Because it is about the file. We
will deal with it later.