Refactor Reader and Objects

[RenatoGeh]

All objects should take as arguments to their respective constructors four parameters:

i - the i-th column in grid (position).
j - the j-th row in grid (position).
o - the orientation (e.g. north, south, west, east).
tp - the type of this object (e.g. "bucket", "dead", etc.)
args - a table containing type specific arguments.

Reader should pass all these arguments the same way for all objects. Maybe rename all tps the same name as their respective classes, avoiding manually inputting new objects in reader.