Use global proxy URL (SingleLineSearch).

* Replace <proxyurl/> with <useproxy/>.
Merge branch '#60/use-global-proxy-url-on-geocoder' into develop
Update SingleLineSearch to use new Geocoder properties.
Add method for migrating SingleLineSearch config.
Rename SingleLineSearch to GeocoderComponent.
Merge branch '#64/update-geocoder-component-properties' into develop
Update HeaderControllerWidget config with latest geocoder structure.
Fix issue caused by missing <geocoder/>.
Clean up.
Merge branch '#64/update-header-controller-widget-config' into develop