This commit upgrades to Spring Boot 1.4.0.RELEASE and bumps to Java8. It
also migrate the cache library from Guava to Caffeeine.
The git and build information are now exposed via the `info` endpoint.
Closes gh-251
This commit splits the feature of Spring Initializr in several modules:
* `initializr-generator` is a standalone library that is responsible for
generating projects based on a `File` directory. It has a minimal set of
dependencies and is not web-related
* `initializr-web` provides the web integration (project generation,
meta-data, etc)
* `initializr-actuator` is an optional module that can be added to
support project-generation-specific statistics
Closes gh-214
