Refactoring.

Use staic option to private functions.
Refactoring Makefile.
Create object class and implement easiest gc.
Make list dv object.
Create tree class.
Make partial class as dv object.
Delete unused rule from Makefile.
Refactoring Parity module for base class updates.
Delete buffer.h and safe_call module.
Create Str class.
Update distribute command for other modules.
Create dv_misc module.
Update restore module for other modules.
Rename dv_misc to dv_error and make exit after dv_perror.
Implement easy cleanup system.

When exit on error, it unregister files to be created.
Rename dv_reference_count to dv_memory.
Create MALLOC and DV_MALLOC macros and make exit soon if failed to malloc.
Change the return value of del method to void; exit immediately if failed.
Exit as soon as possible on error and make simple error checks.
Use cleanup function in distribute command.