Added Static Portrait System

**This build supports static portraits** 
**(static portraits are character sprites that are attached to the dialog box and don't move)**

**[Character.cs, CharacterEditor.cs]**
- Added Portrait List field in character prefab 
    - (You can select many portraits in your project window and drag them into the List field all at once or you can add them one by one) 
- Updated Character Editor profile sprite preview to match the layout of the Say and Choose commands.

**[SayEditor.cs, ChooseEditor.cs]**
- Added a Portrait dropdown menu in the Say and Choose command that allows user to select the portrait that will represent the currently speaking character
    - (This dropdown list only contains portraits from the selected character.)
- Changed the profile sprite preview in the Say and Choose command so that it now displays the currently selected portrait
- The dropdown list and portrait preview will only display if all of the below are true...
    - a character has been selected
    - the selected character has at least 1 portrait attached to their character prefab
    - the selected dialog has a character image attached to its prefab.

**[Dialog.cs]**
- Removed SetCharacterImage() command from inside the SetCharacter() method so that it could be called in the Say and Choose command instead.

**[Say.cs, Choose.cs]**
- On Enter() now calls SetCharacterImage(portrait) using the specified portrait for the command

**[CommandEditor.cs]**
- Edited ObjectField so that it now allows the storing of objects as well as monobehaviours.
    - (This is so I could use ObjectField for the portrait dropdown menu)

**[JumpingPrax, TheFacility, TheHunter]**
- Edited all FungusExample scenes to use the new static portrait system.

**Other changes:**
**[CommandListAdapter.cs]**
- Removed the character limit for command summaries
    - (This change was made so that all the dialog in a sequence can be quickly proof-read simply by expanding the inspector window. This way, when proof-reading a long dialogue sequence, you don't have to click on every single say command just to view the full text.)

NOTE: Fixed a bug where the say and choose command editor would crash if there's no dialog specified.