Merge tag 'release/v1.0.0beta9' into development

Release 1.0.0beta9

* tag 'release/v1.0.0beta9':
  Version Bump to 1.0.0beta9
  Create the 'Duration From Start' strategy
  Gem upgrades, rspectacular installation, replace RVM with rbenv
Version Bump in Gemfile.lock
Add specs to double-check that the absolute strategy works properly with nil dates
Whitespace
Absolute timeframe checks should not care about time zones
Rework the instance #in_progress? method so that it reused logic from #started? and #ended?
Remove non-scoping in_progress methods which I added for a reason but can't remember

All specs pass without them.
Version Bump to 1.0.0beta10
Merge branch 'release/v1.0.0beta10'

* release/v1.0.0beta10:
  Version Bump to 1.0.0beta10
  Remove non-scoping in_progress methods which I added for a reason but can't remember
  Rework the instance #in_progress? method so that it reused logic from #started? and #ended?
  Absolute timeframe checks should not care about time zones
  Whitespace
  Add specs to double-check that the absolute strategy works properly with nil dates
  Version Bump in Gemfile.lock