Added functions & comments

- Added post functions:
    - Added func_post_link() function.
    - Added get_link() function.
    - Added get_title() function.
- Added date functions:
    - Added while_check_date() function.
    - Added func_check_date() function.
    - Added gen_post_date() function. (Still WIP)

To Do:
- Finishing gen_post_date() function