Added blocking script to area 2 exit door to prevent moving to next area before completing the quest objective.

Added SEQ file

- Several bug fixes, layout tweaks, quest tweaks, and more work done on final area.
- Part 4 now allows completion of the main quest. Lots more layout work is needed, but the important aspects that allow for quest progression are in place. Part 4's dungeon is still very bare otherwise.

- The player is prevented from moving beyond the starting location until the main mod quest has progressed to a certain point. This is an added measure to prevent the player from encountering a certain NPC too early in the quest.

- The initial layout and certain key elements have been added to the final area. Lighting, clutter, encounters, etc. still have yet to be added. If you wish to explore the layout, you can use the command "coc GravenDeep03". Note that this is a major spoiler and I recommend avoiding previewing this latest dungeon addition until a later update, since there is nothing done yet in terms of quest progression.