return some error message in global error handler

it is really bad practice for us not to return anything in case of
error. In \BlueLaTex,we always return an error message to briefly
explain what happened
extract configuration loader to own bundle

All bundles potentially use the configuration loader, and to avoid
cyclic dependencies, the best way to do it is to have a bundle whose
single responsibility is to register the configuration loader.
Thus, it will probably be the first bundle that is started and then
everybody is happy and can use it.
test new travis configuration
(hopfully) fix character escape
print potential errors after script execution
make couchdb instance optional
add license file
change return type

a `BlueLet` now returns any result, it is simply ignored, no matter
what. This mainly avoid to map the final `Try` object to make it return
unit.
add service to save a non synchronized resource
add service to retrieve a resource
add service to delete a resource
add service to unregister a user
better Java naming of DMP implementation

Also, we do no more create a DMP class for every actor, but only one created in
the dispatcher and handed down to actors on creation.
Storage manager is now common for every actor

It is created in dispatched instead of in every actors.
cosmetic fixes
issue #2 - synchronization handles multiple files

Until now, a synchronization actor could only handle one file. With this
modification, such an actor can now deals with all synchronized resources given
a paper Id. Each document is to be carried in the synchronization message.
add unit testing of ResourceDispatcher

Update to akka-osgi/testkit 2.2.1
fix bug in ResourceDispatcher thanks to unit test

on actor creation (first "Join" message). the user was not counted in the user
map.
add unit testing for Edit command parser.
fix bug in Edit command parser

'number' parser definition was missing .r operator.