Adding ability to operate on trust passwords to pdbedit. This enables

Adding ability to operate on trust passwords to pdbedit. This enables
new functionality and testing interface for new pdb functions.

Also, quite a bit of objects is being added to pdbedit in order to make
it able to find domain sid automatically (if not given explicitly).
If such amount of "wisdom" is not required to be in pdbedit, I'll move
it to 'net' which will have this new functionality, anyway.

rafal