rename getId to getAggregateRootId for aggregate roots

Makes it obvious that this is used as part of the infrastucture.
moved UUID generators to broadway/uuid-generator
Merge pull request #49 from qandidate-labs/uuid-generator

moved UUID generators to broadway/uuid-generator
Tweak to SELECT statement in DBALEventStore for PostgreSQL - Fixes #52

PostgreSQL forces all column names to lowercase. This causes issues with
the recordedOn colum in the SELECT statement, as the row map winds up with
parameters that are all lowercase instead of the required camel case for
the recordedOn column, and then causes errors elsewhere in the class.

This fix changes the column name the be recorded_on instead of recordedOn,
so that it is no longer an issue. This change is for the database only and does
not affect the key name in any domain object.
Merge pull request #55 from mbadolato/change_column_name_in_dbal_event_store

Fixes #52 - Tweak to SELECT statement in DBALEventStore for PostgreSQL
Merge pull request #39 from brightmachine/change-getId-to-getAggregateRootId

rename getId to getAggregateRootId for aggregate roots
tag 0.2.0
Merge pull request #57 from fritsjanb/tag-0.2.0

Update branch alias + README regarding 0.2.0
Remove Uuid component from readme + fix SagaScenarioTestCase
Merge pull request #59 from fritsjanb/uuid-fix

Remove Uuid component from readme + fix SagaScenarioTestCase