Add SearchResultKind.UNKNOWN to the analysis server API.

This resolves an inconsistency between the spec and the analysis
server behavior: the server returns a SearchResultKind of UNKNOWN if
the MatchKind from the analysis engine is one of the following types:

- ANGULAR_REFERENCE
- ANGULAR_CLOSING_TAG_REFERENCE

R=brianwilkerson@google.com

Review URL: https://codereview.chromium.org//488103003

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@39411 260f80e4-7a28-3924-810f-c04153c831b5
remove unused CompilationUnit and related classes and methods

BUG=
R=messick@google.com

Review URL: https://codereview.chromium.org//490923002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@39412 260f80e4-7a28-3924-810f-c04153c831b5
include inherited members in invocation suggestions

BUG=
R=jwren@google.com

Review URL: https://codereview.chromium.org//489813002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@39413 260f80e4-7a28-3924-810f-c04153c831b5