some work on the new model
[new model] implement more of it
[new model] more work, need to implement parser
[new model] fix parsing (still simple-minded)
[new model] element cache
[new model] element change notifications
[new model] navigator
[new model] fix navigator
define system features as enum (instead of strings)
[new model] fix parsing; improve navigator
[new model] add document provider to support working copies
[new model] add outline support
[new model] fix document reconciling
workaround for xtend issue with nested class
[new model] improve open action, link with editor, label provider
restore some stuff for old model
amend tasks
[new model] implement ErlSource in Java (for non-static nested class)
small fixes
workspace tests reset new model too