Data-Review: Saving all the column fields of object-row done.

**Updated Data-Review to fulfill basic saving requirements:**
- Possibly used already available methods to save ```GAttributes```, ```GRelation```and common fields.
- Every change in column is checked. Showing the same before ```Save``` or ```Cancel```.
- After taking confirmation from user (about changes) resource row is saved.

**Other Changes:**
- Some fields like ```featured```, ```altnames``` etc. are added into ```get_node_common_fields()```
- ```get_node_metadata()``` changed:
  - added some missing attributes to list.
  - Made the function compatible with *PEP8* standard.