support bind uri param (#1612)

* support bind uri (1)

* uri binding successful run

* fix vet warning: github.com/gin-gonic/gin/internal.Param composite literal uses unkeyed fields

* fix code style

* update function name

* fix test function signature

* add test for CanSet

* update readme and add test case

* remove internal.Params

* add coverage

* fix warning

binding/binding.go

@@ -36,6 +36,13 @@ type BindingBody interface {
 	BindBody([]byte, interface{}) error
 }
 
+// BindingUri adds BindUri method to Binding. BindUri is similar with Bind,
+// but it read the Params.
+type BindingUri interface {
+	Name() string
+	BindUri(map[string][]string, interface{}) error
+}
+
 // StructValidator is the minimal interface which needs to be implemented in
 // order for it to be used as the validator engine for ensuring the correctness
 // of the request. Gin provides a default implementation for this using
@@ -70,6 +77,7 @@ var (
 	ProtoBuf      = protobufBinding{}
 	MsgPack       = msgpackBinding{}
 	YAML          = yamlBinding{}
+	Uri           = uriBinding{}
 )
 
 // Default returns the appropriate Binding instance based on the HTTP method