Refactor process package and introduce ProcessManager{} with tests (#75)

* Add a process.Manager singleton with process.GetManager()

* Use process.GetManager everywhere

* Fix godoc comments for process module

* Increment process counter id after locking the mutex

routers/admin/admin.go

@@ -246,7 +246,7 @@ func Monitor(ctx *context.Context) {
 	ctx.Data["Title"] = ctx.Tr("admin.monitor")
 	ctx.Data["PageIsAdmin"] = true
 	ctx.Data["PageIsAdminMonitor"] = true
-	ctx.Data["Processes"] = process.Processes
+	ctx.Data["Processes"] = process.GetManager().Processes
 	ctx.Data["Entries"] = cron.ListTasks()
 	ctx.HTML(200, tplMonitor)
 }