Sheryl removal of implicit extension in overrides main properties seems to be a work around to jspm build bug related to external dependencies entry map.
The list of external dependencies needed to be updated.
Coverage remained the same at 12.138% when pulling ffbf70be6b42f513a3330b352894a864de3b33ac on dinoboff:fix-build into 39272e940fb484114d1c5a63b6116117286b3cd1 on singpath:master.
Sheryl removal of implicit extension in overrides main properties seems to be a work around to jspm build bug related to external dependencies entry map.
The list of external dependencies needed to be updated.
Fix #144