Implement ChF

[SamyaDaleh]

Improvement of buGHR by Chiang and Fu 1984.

Init and C1 like #190.

S1:
[A -> alpha dot a beta gamma, i, j], [a, j, j+1]
_________ beta =>* epsilon
[A -> alpha a beta dot gamma, i, j+1]

S2:
[C -> gamma dot a beta', i, j], [a, j, j+1]
______ B =>* C AND alpha beta beta' =>* epsilon
[A -> alpha B beta dot gamma, i, j+1]

C2:
[C -> gamma dot E beta', i, j], [E -> delta dot, j, k]
__________ i < j AND B =>* C AND alpha beta beta' =>* epsilon
[A -> alpha B beta dot gamma, i, k]

Source: Sikkel, Parsing Schemata p. 115