Merge pull request #198 from alxhub/master-v0.2

Transaction object has appropriate constructor.
Merge pull request #199 from alxhub/master-v0.2

Now passing schema object tests for patch() support.
Reinstate multiplexer_test.dart
Delete obsolete runtime/entity folder
Reinstate batching tests
Reinstate branching tests
Adapt cache to new type system; reinstate tests
Reinstate dedup test
Reinstate error test
Fix transactional API codgen; reinstate tests
Merge pull request #197 from yjbanov/test-fixes

Test fixes
Merge pull request #200 from alxhub/master-v0.2

Fix test for observable .local.
Fix (un)marshalling logic; enable tests
Merge pull request #201 from yjbanov/proxy-client-fixes

Proxy client fixes
Merge pull request #202 from alxhub/master-v0.2

Generation of base.dart with mixologist by Barback transformer.
Updates to multiplexer_test.dart
Rename multiplexer_test to handler_test.
Merge with latest changes.