As now with spring boot 1.4 there is a special goal for generating the build-
information, we use it for displaying the version in spring boot admin. The old
info.version property still works but is deprecated. From now on
build.info.version is taken into account.

The polling in the UI is replaced with server side events. Status changes are
now reported immediately from the admin server to the UI.

remove logfileEndpoint
rename logback.xml to logback-spring.xml in samples

fixes #98