Forward compilation data as events

[skyluc]

Right now, the result of a compilation request is a simple boolean. It is a bit light.

The information that Scala IDE would like in a perfect world:

• List of the files about to be compiled
• Errors and warnings as they are discovered by the compiler
• Delta of the content of the output folders (added, removed, modified files), to be able load the new data in the Eclipse Java model

The data should reference which project it is related to.

If we get everything as one complete update at the end of the compilation of each project, it is fine too.