Use an Integer instead of an Array for error count.

Using array for error count consumes lots of memory when
retry_limit is large. We don't use an item in @error_history,
so we can use simply number count instead of array based approach.
Merge pull request #386 from fluent/use-num-count-for-retry-count

Use an Integer instead of an Array for error count.
Dump version info at dry run mode
Merge pull request #388 from fluent/add-start-log-at-dry-run

Dump version info at dry run mode
V1's escaped parameter should be unescaped at dump process
Fix typo and add test
Merge pull request #389 from fluent/unescape-parameter-at-v1-config-dupm

V1's escaped parameter should be unescaped at configuration dump phase
Add include_source_host options to in_syslog. fixes #390
fix debug_agent unix_path type
Merge pull request #392 from sonots/fix_debug_agent_unix_path

fix debug_agent unix_path type
Add explicity for EventStream
 * show it explicity by NotImplementedError that EventStream is abstract class
 * add comments to describe difference between ArrayEventStream and MultiEventStream
 * remove comment-outed methods of ArrayEventStream to break interoperability of EventStream
 * remove comment-outed IoEventStream:
   * that is not implemented and is not going to be implemented
   * that is danger because it require io-stream to be opened until the EventStream is destructed
add a link to Fluentd UI
Merge pull request #391 from fluent/include-source-host-in_syslog

Add include_source_host options to in_syslog. fixes #390
add detach to Closer
Merge pull request #394 from taichi/detach_closer

Closer should detach own timer to prevent object leak
Fix broken badge URL
Add apache_error format to parse Apache error logs
Merge pull request #396 from fluent/add-apache-error-log-format

Add apache_error format to parse Apache error logs
Merge pull request #395 from camelmasa/fix-broken-badge

Fix broken Code Climate badge URL
Update README.md