remove unused BusyIndicatorRunnableContext
small fixes in Util
move backend interaction in model to BackendUtil
move ErlMember to erlang model
moved top model classes and interfaces to their own package
extract ModelSearchService from ErlModule; needs renaming
remove ErlangToolkit, use services from ErlangEngine directly
arranged model classes a bit for better cohesion
extract ExternalKind from ErlModel
move cache to separate package
more model reorganizing, extract services and stuff
moving some more classes
make IErlangEngine generic
add javax.inject library
make ExecutableExtensionsFactory use ErlangEngine to inject services
make XrefService injectable and let ErlangEditor to get it from there
make services injectable with ErlangEngine fields
inject xrefservice in callhierarchyview
make IndentService injectable
fix .gitignore files