remove `spool` parameter from swiftmailer config. fixes #1993
Merge pull request #2070 from craigh/mailerFix

remove `spool` parameter from swiftmailer config. fixes #1993
correct dispatch/display of configuration template for system plugin.
create js file for faster inclusion in page over call to controller. refs #1790
compile js routes for multiple languages as available
make prefix match the generated routes.
change hard-coded string to provided constant
inject controller_helper instead of full container (good call @cmfcmf)