Refactor spring-boot-loader to work directly with low level zip data
structures, removing the need to read every byte when the application
loads.
This change was initially driven by the desire to improve tab-completion
time when working with the Spring CLI tool. Local tests show CLI
startup time improving from ~0.7 to ~0.22 seconds.
Startup times for regular Spring Boot applications are also improved,
for example, the tomcat sample application now starts 0.5 seconds
faster.
By default it is on, but you can switch it
off (`-P '!integration'`) to ignore integration tests
and get a faster build.
.travis.yml uses this feature so that it doesn't keep
failing on a timeout.