Auto Updating Spring Placeholder Values

2. Support XML config placeholders
3. Add more tests to cover all kinds of cases
4. Update apollo demo to adapt for auto update functionality

add nested property test

add xml config test for PR #962

Multimap并未严格保持@EnableApolloConfig注解中namespace定义的顺序。

update code style

minor fix

Support apollo config injection in Spring Boot bootstrap phase

2. Reorganize the feature to provide the ability to inject apollo
configs in Spring Boot bootstrap phase
3. Add more integration tests to cover different scenarios
4. Update apollo-demo to show this apollo bootstrap config feature could
be used with @ConditionalOnProperty

Fix ConfigChangeContentBuilder update item issue

hibernate will persist every changes made to entities during the session, so in ConfigChangeContentBuilder case, we should clone the entity first to not trigger unnecessary writes to the db

version to 0.10.0-SNAPSHOT