Refactor

Box module and several processors are rewritten. Error reporting is also improved in this pull request. See details below.

## Box Module

`Box.process` will check the modification time of files now. You can check if a file is changed from `file.type` variable.

- **create** - New file
- **update** - File is updated
- **skip** - File is unchanged
- **delete** - File is deleted

## Processor

All data will be saved to cache database now. It can save a lot of time for source file processing.

## Error Reporting

[Domain](http://nodejs.org/api/domain.html) module is used renderer, processor, generator and filter now, which brings you better error reporting.