Normalise path names for OSX local filesystem

Fixes #194 Fixes #451 Fixes #463

local/local.go

@@ -100,6 +100,7 @@ func (f *Fs) String() string {
 
 // newFsObject makes a half completed Object
 func (f *Fs) newFsObject(remote string) *Object {
+	remote = normString(remote)
 	remote = filepath.ToSlash(remote)
 	dstPath := f.filterPath(filepath.Join(f.root, f.cleanUtf8(remote)))
 	return &Object{

local/normalise_darwin.go

@@ -0,0 +1,12 @@
+// +build darwin
+
+package local
+
+import (
+	"golang.org/x/text/unicode/norm"
+)
+
+// normString normalises the remote name as some OS X denormalises UTF-8 when storing it to disk
+func normString(remote string) string {
+	return norm.NFC.String(remote)
+}

local/normalise_other.go

@@ -0,0 +1,8 @@
+// +build !darwin
+
+package local
+
+// normString normalises the remote name if necessary
+func normString(remote string) string {
+	return remote
+}