Adds CLI support for partials with relative paths

bin/mustache

@@ -78,7 +78,13 @@ function readPartials (cb) {
   var partialPath = partialsPaths.pop();
   var partial = fs.createReadStream(partialPath);
   streamToStr(partial, function onDone (str) {
-    partials[getPartialName(partialPath)] = str;
+
+    var keysArray = getPartialNames(partialPath);
+
+    keysArray.forEach(function addPartialNames (key) {
+      partials[key] = str;
+    });
+
     readPartials(cb);
   });
 }
@@ -131,6 +137,27 @@ function hasVersionArg () {
   });
 }
 
-function getPartialName (filename) {
-  return path.basename(filename, '.mustache');
+function getPartialNames (filename) {
+
+  // get path relative to the template file
+  // in order to use e.g. {{> ../common/footer }}
+
+  // before, {{> footer }} used the first -p file with the filename 'footer'
+
+  // the second replace is for a consistent form between platforms
+  // without it, you would have to use {{> ..\\common\\footer }} for windows
+  // and {{> ../common/footer }} for *nix
+
+  // this can be extended to the mustache API by using the relative path as
+  // the key in the partials object
+  // e.g. mustache.render(template, view, { '../../common/footer': '...' })
+  var relativePath = path.
+    relative(templateArg, filename).
+    replace('.mustache', '').
+    replace(/\\{1,2}/g, '/');
+
+  return [
+      path.basename(filename, '.mustache'),
+      relativePath
+    ];
 }