Update Options Struct
Fix syntax error
Use `ga_debug` only in development

Before, it checked if not in `build`. I think to check for development is more accurate.
Actually use `ga_debug` when `debug` is `true`
Merge pull request #7 from tmaier/master

Fix for #6  (syntax errors etc. related to ga_debug)
Merge branch 'master' into features/domain_name_and_allow_linker

Conflicts:
	lib/middleman-google-analytics/extension.rb