- base
	* error/exception handling
	* security
	* module
	* application
	* http exception
- validators
	* type conversion rules
	* CompareValidator::clientValidateAttribute(): search for "CHtml::activeId"
	* FileValidator, UniqueValidator, ExistValidator, DateValidator: TBD
	* consider merging UniqueValidator and ExistValidator and using a NOT property.
- console command support
- built-in console commands
	+ api doc builder
		* support for markdown syntax
		* support for [[name]]
		* consider to be released as a separate tool for user app docs
- caching
	* a way to invalidate/clear cached data
	* a command to clear cached data
- db
	* DAO
	* schema
	* AR
	* document-based
	* key-value-based
- logging
- i18n
	* consider using PHP built-in support and data
	* message translations, choice format
	* formatting: number and date
	* parsing??
- helpers
	* array
	* image
	* string
	* file
- web: TBD
	* get/setFlash() should be moved to session component
	* support optional parameter in URL patterns
- gii