Fixes issue with the boolean parameters that will always resolve to "true"

From comment in
https://library.octopusdeploy.com/#!/step-template/actiontemplate-iis-apppool-create

See
http://www.jonathanmedd.net/2012/05/powershell-quick-tip-converting-a-string-to-a-boolean-value.html
Merge pull request #97 from timhobbs/master

Fixes issue with the boolean parameters that will always resolve to "tru...