Fix #111, fix 110

Fix crash with mutating array when selecting monsters. With only the type hint the local array would not reinitialize in Godot 3.1 alpha 2, causing a crash

Grid -> GameBoard
Add types to GameBoard
The pathfinder node doesn't inherit from anything. It uses an Astar node
to find the path between 2 points on a 2d grid

needed as I changed how RectExtents works

closes #108

Most of the work for #108

Currently only resizes uniformly around the rectangle's center! It needs
more code to add support for all 4 anchors. Or just fixing the issue
below, restoring the move tool's functionality and deselect, could do
the trick

RectExtents's internals changed a little, now it calculates its own
_rect property, a Rect2, based on its size and offset

Known issues: The input code blocks the move tool and selecting other
nodes at the moment

This is an exercise to get a sense for Godot's EditorPlugin API and
prepare some tutorial on the subject.

Big thanks to xphere, I used his godot-zone plugin as a reference to get
started :)

Closes #109
It works in a basic fashion but the UX needs polish. Help welcome!

LocalMap now initializes the actions with itself.
Added a method to start a dialogue on LocalMap
Moved files from pawns/interactives/ to pawns/
Removed now obsolete Dialogue.tscn and Dialogue.gd files

* Removed events from grid in local map

Closes #50

Also created boiler plates for pawns that have some type of interaction with the player. They work with both raycasts (in case we want something like pokemon) and area2ds for something that should only trigger on contact. 

* MapActions created and grid removed from interactions

I used @nhydock's approach (sent via discord) to provide the correct nodes for the interactions aka using it's path. This implies on having to left click > edit children on every InteractivePawn after adding the desired actions. One alternative would be to provide the actions' scenes with the UI node, this way, each of them could display the UI when needed, without having to set node paths to them. Not sure which approach is better.
The actions are added to the InteractivePawn's `Interactions` node. I left one node in the map which starts an encounter after a dialogue, as mentioned by @NathanLovato

Refactor battlers to make it easier to edit and extend them

Also improved combat actions and moved some calculations out of battlers and into the actions instead.

closes #101

Leader and followers created from party in LocalMap

Characters dialogue database and portraits added

Fixed CoC link in README

I opted to serve the textures with a function in the database that handles the fetching of the desired texture. It looked more natural, easier and more natural than to add this logic to the Dialogue.gd since all it does is returning the Dictionary with the dialogue phrases, the actual building of the interface happens in DialogueBox. There, I fetch the textures by reaching to the database. 

Closes #92

Closes #90

After the filename of the CoC changed, the README was not updated.

Fix #88 - missing skills now decrease mana properly

I tried to simplify the code, shorten the player script
The DialogueBox now uses the pressed signal on buttons for better mouse and touch support in the future