…ication

This commit adds changes to allow partial writes to files. Mainly,
SendPartialObject : allows modify or append operations on a file
BeginEditObject   : instantiates the start of edit operation on a file,
                    and is called before using SendPartialObject
EndEditObject     : commits changes to a file

Currently libmtp sends sequence of BeginEditObject, SendPartialObject
and EndEditObject MTP events for file operations like rename and duplication

Signed-off-by: Murali.S.R <muralidhar.s.r@huawei.com>