Edit (2015-05-06): Technically, as of when this answer was originally answered, the answer is "No, you cannot add this functionality in any way". However, this may mean I simply do not know if there is a way.
Ah, I finally noticed how PCManFM does it while watching a video review of said OS.
To open a terminal in a folder, simply move "outside" the folder, right-click on said folder, and the option to open folder in terminal will be in the right-click menu.
For example, say I want to open a terminal in my "Downloads" folder:
- Move "outside" or "above" the folder, which in this case would be my home folder,
- Right-click on the "Downloads" folder
- Select "Open in Terminal"
After following these steps, a terminal should open, with the path set as