Merge remote-tracking branch 'upstream/develop' into develop

* upstream/develop:
  Release Notes updated
  Bug fix for nested commands
  Fixed coverage tool failure to find code
Merge remote-tracking branch 'upstream/master' into develop

* upstream/master:
  Release Notes updated
  Increased version number and added gemspec
Merge branch 'master' into develop

* master:
  Release Notes updated
  Made pre-release executable
  Fixed broken validation method. TODO: some tests around this.
  Version capability added
Set version to 1.2.1 in lib/argumental/version.rb
Release Notes updated
Merge branch 'release/1.2.1'

* release/1.2.1:
  Release Notes updated
  Set version to 1.2.1 in lib/argumental/version.rb