Support loading a `.spring-boot-devtools.properties` file from the
users home folder. The property file can be used to customize settings
that make sense on a per-user basis, but might not want to be checked
into the project.
Fixes gh-3151
Update DevToolsPropertyDefaultsPostProcessor to set the following
additional template cache properties to `false`:
spring.freemarker.cache
spring.groovy.template.cache
spring.velocity.cache
spring.mustache.cache
Fixes gh-3125
The FileWatcher sometimes generates multiple events for a single change
and if there is a slow shutdown hook the second one can come in before
the context is closed, leaving it in a tricky state. This change
attempts to stop the file watcher as soon as it detects a change
(the stop() method is called in the listener, which normally happens in
the same thread as the scan).
Fixes gh-3097
