First skeleton draft for cli
Starts to handle getAttachments
Can use flags for command options
Deal more cleanly with printing errors
Introduced AttachmentReader
Added putAttachment and deleteAttachment
Using polymorphism to avoid duplication
Added tests skeletons to make sure they won't be forgotten
Added getAttachment command
Handles the -f flag of putAttachment properly
Let easily run every checks

If we can't even build the jar, we should fail, even if we pass every tests
It could be possible for the latter to pass while the former fail, for example
if we try to build test classes in the jar (since we then don't have junit in the classpath)
Added -f for deleteAttachment
Extracted method buildDokuClient
Reduced verbosity
refactored tests
refactored tests