parsing partially annotated input

[masashi-y]

Read inputs such as: "(NP (NP/NP Michael) (NP Jordan)) is a professor at (NP University of California, Berkeley) (. .)" and run A* parser under the constraints that the resulting trees conform to the input annotation.

TODO:
The beta parameter, seen rules, category dictionary may better be disabled some times so there will be less chance that the parser outputs no trees.