Add template func FileSize

modules/base/tool.go

 }
 
 // FileSize calculates the file size and generate user-friendly string.
-func FileSize(s uint64) string {
+func FileSize(s int64) string {
 	sizes := []string{"B", "KB", "MB", "GB", "TB", "PB", "EB"}
 	return humanateBytes(uint64(s), 1024, sizes)
 }

templates/repo/single.tmpl

                     {{if .IsDir}}
                     <a href="/{{$username}}/{{$reponame}}/tree/{{$branchname}}/{{.Path}}">{{.Name}}</a>
                     {{else}}
-                    <a href="#">{{.Name}} - {{.Size}}</a>
+                    <a href="#">{{.Name}} - {{FileSize .Size}}</a>
                     {{end}}</td>
 	                <td class="date"><time datetime="{{.Created}}" data-title="true" title="{{.Created}}">{{TimeSince .Created}}</time></td>
 	                <td class="text">{{.Message}}</td>