Add two more head finding rules to fully annotate PTB corpus.
Add two more head finding rules to fully annotate PTB corpus.

These two rules aren't in Collins' thesis, yet they appear in the Penn
Treebank...

gef756/meta,husseinhazimeh/meta,husseinhazimeh/meta,esparza83/meta,saq7/MeTA,gef756/meta,gef756/meta,husseinhazimeh/meta,saq7/MeTA,esparza83/meta,gef756/meta,esparza83/meta,esparza83/meta,saq7/MeTA,gef756/meta,husseinhazimeh/meta,husseinhazimeh/meta,esparza83/meta