Tokenize whitespace characters when verbose mode

For example, If tokenizer is given following;

    my $foo;
    1;

it will tokenize like so;
[ VarDecl, WhiteSpace(space), LocalVar, SemiColon,
  WhiteSpace(newline), Int, SemiColon, WhiteSpace(newline) ].
Merge pull request #20 from moznion/feature/tokenize_whitespace

Support to tokenize whitespace characters on verbose mode