v0.5.0 Projection refactoring

Added

• Allow services referenced in config to be prefixed with @ (#41)
• Add FQCN alias for Prooph\Common\messaging\MessageFactory (#45, thanks to @gquemener)

Deprecated

• Deprecate using a FQCN instead of a service id for projections.
  Support for this kind of configuration will be removed in v1.0. (#43)

Changed

• Enhance validation of repository configuration (#44, thanks to @gquemener)

Removed

• [BC-BREAK] Remove automatically created aliases for projections and projection-managers (#43)

Fixed

• Fix projection configuration via tags (#42, #43)