Update troubleshooting.md

I never thought of looking in the aliases section of the documentation...
Extended the fetchFile() method of the ComposerRepository class to be
able to deal with http basic auth. In case the remote resource responds
with a 401 ask the user for access credentials and retry quering the
resource again.
Moved 401 handling from ComposerRepository to RemoteFilesystem and
displaying the url when asking for the credentials.
Reverted the last changes. Changed logic in callbackGet() method to
respect the 401 handling also if STREAM_NOTIFY_FAILURE fires as on my
local machine the handling of STREAM_NOTIFY_AUTH_REQUIRED never got
executed.
Removed dead statement.
added artifact repository initial functionality
added logging for wrong files
added verbose logging for artifact directory scan
added documentation entry about artifact usage
added support for nested location of composer.json files within artifacts
added fixture dummy artifacts
set version to dev-master to artifacts without version
travis locale version order fixed
modified test in order not to depend on sorting order
changed documentation typo
Removed dev-master as default version for versionless artifact
Added notice about need of zip extension
Added test for ComposerRepository::whatProvides
Added support for the alias of an aliased package
Fixed update alias packages in dry-run mode