Search plugin

Ok, the name sucks and can be discussed.

Right now this enables selections of tokens within the current document by an input form, that can also handle regular expressions.

This plugin might grow to something far more sophisticated in the distant future and might be used for making queries across whole treebank databases at some point - always using external services for that task of course.


The way it is right now I find it personally already highly effective, especially taking the last PR #85 into account, which enables changes across more than one token in the relation plugin.

One could find all prepositions by entering them in an input field and apply all changes to that through a different plugin.


A challenge here are of course languages with a different charset such as Greek! We'll open an issue for that.