Document how to access internal dict for faster reads

[Downchuck]

Currently, todict makes a copy of the full structure. Simply accessing (or documenting) the internal dict is much faster than using setattr/getattr and reflection.

[yihuang]

Why not post some code, i'm not sure exactly what you propose. ;D

[Downchuck]

This may not even need code; it's simply a documentation note now.

entity.__dict__

is faster, when appropriate, for accessing fields than using setattr/getattr or creating a dictionary through:

entity.todict()

[yihuang]

__dict__ is different from todict, you get a object instance for submessage instead of dict.