bot: Enumerable learned concat

also removed unnecessary const constructors
example/bot_retained: use the same path for dart.js

makes cleaning it up later with clever hop tricks more easy
dart2js
hop_tasks: unit_test: TODO on printing runningTime
bumped to SDK 0.4.2.2 r20138
pub: moving html5lib and browser to dev_dependencies
dart2js
pub: bump min version of packages to align with SDK
flagging v0.16.0-dev
hop_tasks: better logging in unittest
finished cleanup on String.concat
cleanup for List.getRange -> sublist
bot_retained, bot_html: fixed the rest of the important deprecations
updated changelog
hop_tasks: dart_analyzer: added machine-format flag, abbr for other flags
test: hop_tasks: dart_analyzer: fewer, shorter tests
test: returning Future from test methods is nice
test: more Future test cleanup
hop: fixed crash in ConsoleContext by fixing regression in subCtx disposal
hop: tweaked output level of Run time to Level.FINER