client.url fix, as well as win32 tmp file location fix

This fixes two things - the first fixes a hard error caused by mox.js trying to write files in a protected area on windows. The patch makes it write safely to the user's temp directory. The second fix adds an optional domain to the options object passed to `createClient` so that client.url(...) can return a fully qualified URL. Without a domain property, the `url`, `http` and `https` functions do exactly the same as before. Having the fully qualified URL makes it easier to use noxmox alongside libraries such as `knox`.