Variables including @ character in name aren't substituted

[KennethBates]

If you intend on substituting a variable whose name includes an @ character (e.g. @foo), this variable is unable to selected for substitution with Octostache syntax (#{@foo}). The parsing of identifiers doesn't include @. We should consider extending this to include @.

Report: https://help.octopus.com/t/octostashe-reference-json-property-named-with-an-symbol/28724/3