FIREBREATH-251 Patch

This patch fixes the issue mentioned in FB-251, allowing the proper Wix configuration for a per-machine installer. The change is small, an additional cmake variable being set, based on the status of FB_ATLREG_MACHINEWIDE, which is the used in then TemplateInstaller.wxs for project generation to allow for proper configuration of a machine-wide installer for windows.

See: http://jira.firebreath.org/browse/FIREBREATH-251