Add features on router

Add :

• Gin Tonic Group route features
• default route group for no group
• func to allow init later a status router
• func to allow register in group a status router
• func to allow register in group a static router
• interface for Register in Group in router package
• check in header to avoid null map/slice

Change :

• issue #14 : add func SetGinHandler and mark SetGinHnadler as deprecated
• Issue #16 : fix init headers model
• bump dependancies