Removed misd/guzzle-bundle and use guzzle/guzzle service
Change README.md increase version to install from RC2 to RC4
Fix version to install at RC3 in README.md
Fix dependance with guzzle #112

Switch from guzzle/http to guzzle/guzzle
Delete MappingCollection replaced by ConnectorMapping #108

Delete Mapper/MappingCollection replaced by
Pim/Bundle/ConnectorMappingBundle/Mapper/MappingCollection
Use statements changed or added