Reload template by check file modified time.

Reload template by check file ModTime each time access a template. This
should be time consumed(?) and has a performance issue. Should create a
thread and monitor file change. If changed reload the template.
Support Informal Parameters in component A
Can use db.QueryParser as parameter in service.
what?
coercion of time.Time
Add session support, now support redirect to page.

But memory leak, add session timeout.