Implemented Portals!

So Portals have been added to the game, admittedly only pawns can use them, but its a start!

Portals can be moved to any currently unoccupied tile, you can only move your own portal, white being red, black being blue (colours will probably change, and portals will get a more portally look later on)

Currently Pawns can do all there regular moves into a portal, and pop out in the direction they came into it, so if it moved forward(one or two spaces) it will pop out on step forward from from the neighbouring portal. This works with diagonal movement so long as they're is a piece to take diagonally  from the other portal. This also works with special moves like En Passant 

Going to start working on the rest of the pieces to get them interacting with the portal

Known Bugs

1. currently you can take the opposing portal with a piece that isnt a pawn. This will get fixed as the other pieces know how to handle portals.
2. If a pawn goes through a portal and ends up back at the starting row, it can do its "first move up 2" again. This is because originally i coded chess, and in chess the pawn has no way back to its starting position, in fact, it has no way to move backwards at all...
3. Issue with checkmate not being hit if the king isn't in check itself, you will just be unable to make moves and no checkmate message will appear. This will be fixed in a quick update shortly

Picture below shows a situation where it is checkmate, but no win message has come up (also shows a portal in the taken pieces pile)