Remove unnecessary code.

Ruby よくわからないので間違ってたらごめんなさい。
Support read_from_head without pos_file option

Including InputTestDriver fix and adding more tests from pull #247
Merge pull request #346 from fluent/support-read-from-head-without-pos_file

Support read_from_head without pos_file option
Serialize plugin shutdown order. Shutdown Input first for safety
Fix in_tail shutdown race condition problem
fix multiline parsing without firstline
use "be true" and "be false" insteaf of be_true/be_false
use failure_message
use rspec3
Merge pull request #349 from sabottenda/rspec3

use RSpec 3 for test and fix deprecate syntax
add a test case for parsing multiline without format_firstline option
use expect syntax instead of should syntax
Merge pull request #351 from sabottenda/use-expect-syntax

Use expect syntax instead of should syntax
Merge pull request #345 from methane/patch-1

Remove unnecessary code.
Merge pull request #348 from fluent/fix-in_tail-shutdown

Fix in_tail shutdown race condition problem
Merge pull request #350 from sabottenda/fix-parsing-multiline

Fix multiline parsing without format_firstline
Add comment to each plugin shutdown
Change XXXParser#call API to support multi events with block based parsing
Add CSVParser and TSVParser tests
Fix forgetting return call error