Implement punctuation

[leoalenc]

This issue is closely related to #84. Its goal is to implement basic punctuation:

1. In coordination structures, see Implement coordination #84.
2. Sentence delimitation:

O cachorro latiu?
Que cachorro latiu?
Quem prendeu o cachorro?
O cachorro latiu.

In case of two, it is important that the punctuation contribute a feature marking the ilocutionary force of the sentence: declaration, question, etc.

The present issue is very important to define a workflow of manual changes in the grammar in connection with changes with the help of the questionnaire.