GetContentStream / GetContentStreamURL

For GetContentStream and GetContentStreamURL :
 - Documenting the optional "streamId" parameter (for renditions)
 - Setting the correct values for the "download" parameter ('inline' or 'attachment')
Fixing policies, addACEs and removeACEs parameters

Fixing policies, addACEs and removeACEs parameters for methods :
createFolder
createDocument
createDocumentFromSource
createRelationship
createPolicy
createItem
checkIn
Corrections on parameters documentation
Merge pull request #8 from TBOU/master

Various fixes