Update Error message quotes to single quotes

* helps reduce noise when transmitting errors via JSON.

for #199

util.go

@@ -13,8 +13,8 @@ const (
 	leftBracket        = "["
 	rightBracket       = "]"
 	restrictedTagChars = ".[],|=+()`~!@#$%^&*\\\"/?<>{}"
-	restrictedAliasErr = "Alias \"%s\" either contains restricted characters or is the same as a restricted tag needed for normal operation"
-	restrictedTagErr   = "Tag \"%s\" either contains restricted characters or is the same as a restricted tag needed for normal operation"
+	restrictedAliasErr = "Alias '%s' either contains restricted characters or is the same as a restricted tag needed for normal operation"
+	restrictedTagErr   = "Tag '%s' either contains restricted characters or is the same as a restricted tag needed for normal operation"
 )
 
 var (

validator.go

@@ -30,7 +30,7 @@ const (
 	skipValidationTag       = "-"
 	diveTag                 = "dive"
 	existsTag               = "exists"
-	fieldErrMsg             = "Key: \"%s\" Error:Field validation for \"%s\" failed on the \"%s\" tag"
+	fieldErrMsg             = "Key: '%s' Error:Field validation for '%s' failed on the '%s' tag"
 	arrayIndexFieldName     = "%s" + leftBracket + "%d" + rightBracket
 	mapIndexFieldName       = "%s" + leftBracket + "%v" + rightBracket
 	invalidValidation       = "Invalid validation tag on field %s"

validator_test.go

@@ -252,7 +252,7 @@ func TestAliasTags(t *testing.T) {
 	NotEqual(t, errs, nil)
 	AssertError(t, errs, "[0]", "[0]", "iscolor")
 
-	PanicMatches(t, func() { validate.RegisterAliasValidation("exists", "gt=5,lt=10") }, "Alias \"exists\" either contains restricted characters or is the same as a restricted tag needed for normal operation")
+	PanicMatches(t, func() { validate.RegisterAliasValidation("exists", "gt=5,lt=10") }, "Alias 'exists' either contains restricted characters or is the same as a restricted tag needed for normal operation")
 }
 
 func TestNilValidator(t *testing.T) {
@@ -4040,7 +4040,7 @@ func TestAddFunctions(t *testing.T) {
 	errs = validate.RegisterValidation("new", fn)
 	Equal(t, errs, nil)
 
-	PanicMatches(t, func() { validate.RegisterValidation("dive", fn) }, "Tag \"dive\" either contains restricted characters or is the same as a restricted tag needed for normal operation")
+	PanicMatches(t, func() { validate.RegisterValidation("dive", fn) }, "Tag 'dive' either contains restricted characters or is the same as a restricted tag needed for normal operation")
 }
 
 func TestChangeTag(t *testing.T) {