Execution policy to unrestricted

Closes https://github.com/jamesandrewsmith/devtools/issues/12
Merge pull request #13 from jamesandrewsmith/feature/powershell-execution-policy

Execution policy to unrestricted
Merge branch 'master' of github.com:jamesandrewsmith/devtools into feature/windows-packages-install

Conflicts:
	windows/install.ps1
Set execution policy

https://github.com/jamesandrewsmith/devtools/issues/16