Initial gradle build system for randori compiler. Added also gradle wrap...

Submitted again to the correct branch:

Simple gradle build system, it resolves correctly all dependencies in maven repositories, I've removed all jars from lib but had to add compiler.jar.

```
gradle tasks (get a list of all available tasks)
gradle jar (build jar)
gradle install (create source, javadoc and jar archives and publish to local maven repository)
gradle idea (configure for Idea IDE)
gradle javadoc
gradle clean
```

I think next step should be publish to maven central repo through sonatype, someone authoritative for the project should do the process though (https://docs.sonatype.org/display/Repository/Sonatype+OSS+Maven+Repository+Usage+Guide)

I adapted gradle to current directory struture but it might also be a good idea to adapt the directory to gradle/maven standard.