Impl proc's `Die()` method.

1. implement `Die()` method to panic and stop proc's further running.
2. delete default not found template proc.
3. delete gopher_cry image.
Add session module, just part of code.

1. add session module.
2. need redesign Response, to implement http.ResponseWriter interface. so,
have to redesign the execution procedure.
Design some interfaces for session module.
Implement some session module code.
Some session implementations.

1. change password generator util.
2. add some codes of `Session Provider` and `Session Manager` in session
module.
Merge branch 'reconstruction'