MOBSDK-525: base64 encoded streaming

MOBSDK-525: integrated the new CMIS library with AlfrescoSDK. This supports base64 streaming using the new CMISBase64InputStream class.
Also, the latest CMISLog code is in there.

Improvements NOT included: DocumentFolderService returns errors directly from the CMIS library, i.e. as CMISErrors. This should be wrapped into AlfrescoErrors.