Add logging

[jperedadnr]

Fixes #45

Shows the pieces created for instance after changes in decoration:

PieceTable{
 O="Simple text one two three<n>Extra line text",
 A="",
 L=41, pieces ->
 - Piece{type=O, [0, 12], deco{color=0x0000ffff, font['Arial', 17.0, R, N]}, "Simple text "}
 - Piece{type=O, [12, 3], deco{color=0x0000ffff, font['Arial', 17.0, R, B]}, "one"}
 - Piece{type=O, [15, 26], deco{color=0x0000ffff, font['Arial', 17.0, R, N]}, " two three<n>Extra line text"}
}

or after some insertion:

PieceTable{
 O="Simple text one two three<n>Extra line text",
 A=" new",
 L=45, pieces ->
 - Piece{type=O, [0, 15], deco{color=0x0000ffff, font['Arial', 17.0, R, N]}, "Simple text one"}
 - Piece{type=A, [0, 1], deco{color=0x0000ffff, font['Arial', 17.0, R, B]}, " "}
 - Piece{type=A, [1, 1], deco{color=0x0000ffff, font['Arial', 17.0, R, B]}, "n"}
 - Piece{type=A, [2, 1], deco{color=0x0000ffff, font['Arial', 17.0, R, B]}, "e"}
 - Piece{type=A, [3, 1], deco{color=0x0000ffff, font['Arial', 17.0, R, B]}, "w"}
 - Piece{type=O, [15, 26], deco{color=0x0000ffff, font['Arial', 17.0, R, N]}, " two three<n>Extra line text"}
}