Merge branch 'release/v1.3.2' into develop
Multi-thread benchmark.
Thread-safe Ruby UDP sender.
Do not store state in instance variable for thread-safety.
Do not store chunk number.
Fix me some English.
Fix Ruby sender.
Do not remove Airbrake/Hoptoad keys from hash.
Extract error_class and error_message from exceptions.
Always collect file and line for exceptions.
Fix arguments stringification.
Set socket option.
Add benchmark.
Update gemspec.
Version 1.4.0.beta1.
Update Travis CI config.
Update Jeweler, gemspec, add Bundler.
Drop rcov.
Skip Rbx 1.9 for now.
Add rails log tag support.