Use "return" instead of "exit" where possible, especially in
function definitions.
Also fixed the exit codes to match the LSB spec for some specific
conditions (fixes gh-3521).
Fixes gh-3199, fixes gh-3535
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
Phillip Webb
Dave Syer