Merge pull request #3981 from spigad/master

check uuid prefix.
fix import and remove debugging
Fixing failure message from client CAF-268
Create README.md
Removing conflicting option from --instance
Merge pull request #3982 from cinquo/master

Improving failed task/job group messages from client
Fix a couple of printouts
Set X509_USER_PROXY user variable for -p options (X509 is used by PandaServerInterface.put)
Dump the right dict for analyzed lumis. CAF-315
Merge pull request #3983 from mmascher/messages

Fix a couple of printouts
Merge pull request #3984 from mmascher/optional-proxy

Optional proxy
Merge pull request #3985 from mmascher/master

Dump the right dict for analyzed lumis. CAF-315