Making signal handling ruby 2 compatible

by stealing the pattern used in Sidekiq :scream_cat:.
Merge pull request #344 from meatballhat/ruby-2-compatible-signal-handling

Making signal handling ruby 2 compatible
Prepping for v2.5.1 release
Merge pull request #345 from meatballhat/v2.5.1-prep

Prepping for v2.5.1 release
Merge pull request #346 from meatballhat/merging-v2.5-stable

Merging v2.5 stable