Ping services mostly implemented in services.dart
Started PingServiceImpl
TEMPORARY restored ping test
Fixes from merge
Setup listener to handle ping, print, and normal service calls / responses
Full end-to-end working.  Moved mapping to ServiceActionEvent class.  Ready for timing test
Implemented timing tests (BROKEN CODE.  REVERTING)
Fixed timer logic to call back to chrome service for delays.  Cleaned up.
Review fix and setup tests
Review fixes
Switched stream to future
Moved callId logic out of Service / ServiceImpl
Restored mapping instead of closure code for service calls.  Turned sendResponse into void return type
return new future(string) ==> string
consolidated accessor .. remove into remove.  Also, fixed 2 bugs with the removers
Merge pull request #1062 from dart-lang/umop-services-implementation2

Services implementation with example service