fix for activity client options github issue #57
refactored some tests and added new tests for activity client
fixing reap completed pids bug
fixing exponential retry (related to Github PR# 58), restructured tests and added more tests to make sure exponential retry is stable
improvements to executor tests and refactoring more tests
fixing one more test and putting common methods in modules
specifying ruby version in gem spec
adding use_worker_task_list parity with java flow. Refactoring tests
This is a breaking change. This change modifies the basic behavior of default options in ruby flow. Default options, now called registration options, are only used for registration purposes and flow doesn't use them outside workflow/activity registrations. This change gets ruby flow on par with java flow.
Made the changes and added tests to allow workflow class to have multiple workflows and allow workflow clients to start multiple workflows in the
same workflow class. Fixed workflow options a little.
Merging @mjsteger's changes
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Fix issue #37 by covering an edge case

It's possible timer fired to interplay poorly with cancelling the timer,
and this should fix that problem. It may be worth reviewing all
completion locations to ensure that a similar problem is not present
there.
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Making some changes to the test to make it compatible with other test chagnes
Fixing a bug that was preventing workers and pollers to log to the same log file
changing the json structure. json config file will now support only 1 domain per file. Also removing the need to specify the domain within each worker.
making more json settings optional and assigning them defaults - retention_in_days(7), number_of_workers(1) and number_of_forks_per_worker(20)
Fixes to some integration tests. Also adding some utility builder methods.