Add clean support for containers, images and directories.

This feature involve change of naming for images and directories, you will need to clean
directories and images at hand for build before this commit.

Build directories are still in temp directory of the system, images respect the following
name : jolici_[Strategy in lowercase]/[Project name]:[Build identifier]-[Timestamp]

The Build identifier is a key which is the same for every build with the same parameters (language, version and
environment for TravisCi)
Merge pull request #37 from jolicode/feature/clean

Add clean support for containers, images and directories.