move some functions from the scripts in Bosque-UD to this library

[fcbr]

A number of useful methods written for the scripts to fix the issues in Bosque-UD can be imported to this library. Things like isolated?, add-feature, remove-feature, search-features, etc. They should be adapted for the general case and added here.

Optionally (and maybe this is a larger issue) we also started a very simple query language, implemented by the method t? in the scripts that can be finalized and imported here as well. This one, however, needs a better implementation as it is extremely simple, just enough functionality to handle the requirements of those scripts.

Recommend looking at the latest scripts (by date) to see the more fully featured versions of those methods.

[arademaker]

this is a botton-up approach for the library instead of thinking first in the user language for the rules. But I agree that I should start to move these reused functions to the lib.