Merge pull request rubyist#44 from abferm/master

Fix issue rubyist#43 [Value alignment issue on 32-bit systems (ARM)]

Update changelog for 2.2.0

Update changelog for 2.1.7

Update changelog for 2.1.6

Update changelog for 2.1.5

Update changelog for 2.1.4

Update changelog for 2.1.3

Simplify and fix Call() for rate breaker.

Closes rubyist#22

Add changelog entry for 2.1.1

Merge pull request rubyist#21 from rubyist/window

Use a sliding window to track failures / successes