Add nabl-collect-use-task
Added generic filtering/disambiguation higher-order tasks.
Pass context terms as a list and add a context string to identify a filtering/disambiguation context.
Split eclipse and dynamic rule strategies into own files.
Ensure disjoint matches for definitions of position-of-term
Merge branch 'master' of https://github.com/metaborg/runtime-libraries
editor/properties: a default get-editor-properties implementation for the properties view