First version of Check-Command to check the env + installation
Merge branch 'master' into gerrie_check

* master:
  Removed Executable.SSH configuration
  Removed duplicated arguments / options
  Added first version of arguments for CrawlCommand
Next step for check command. Now with configuration checks
Added end message of check command
Merge branch 'master' into gerrie_check

* master:
  Fixed UnitTests with DummyConfig-file
  Fixed unit tests for getArguments in instances
  Merged argument instances into configured instances
  Added ssh-key to config overwrite
  Reworked Gerrie config and make it easier to configure ;)
  Fix path for fixture config file for unit tests
  Move execution of database command to separate method
  Add SSH key option and instances argument to crawl command
  Added new SSH Key option and instances argument

Conflicts:
	tests/Gerrie/Tests/Component/Configuration/ConfigurationFactoryTest.php
Fixed wrong message call
Added 'oh dear' message
Added possibility to set and get database configuration
Added SSH-Key and instance option to check command
Added MySQL / database connection check
Implemented version call for HTTP Data Service
Added DataServiceInterface to enable a unique interface
Removed obsolete whitespace line
Added APIConnectionCheck to check command
Make use of DataServiceInterface in case of type hinting
Add TODO to check the SSH key of existence
Add a version_compare to APIConnectionCheck
Add TODOs to CheckCommand
Add Unit test for APIConnectionCheck
FIx unit test for APIConnectionCheck