Remove logging functionality from TextParsers

Parsers in Fluent::TextParser are utility library.
Current implementaion depends on `$log` and it causes hard to use by other script.

I think $log should be removed from each Parsers.

Pros:
  - code becomes simply
  - other script can use without explicit $log instantiation.

Cons:
  - breaking compatibility with -v option because logging position is changed