Create SpringBootAdminClientAutoConfiguration only when URL is set
Next release
Merge branch 'master' of https://github.com/codecentric/spring-boot-admin into spring-boot-1.2.0

Conflicts:
	pom.xml
	spring-boot-admin-example/pom.xml
	spring-boot-admin-server/pom.xml
	spring-boot-starter-admin-client/pom.xml