Prepare V2.0
Add accessor on FILE descriptor if any
RMID #54

Output can now be determined by users with filename field in
log_params structure.
If filename is an empty string, logs will be written on stdout
else, they will be written in corresponding file (if user has right
to create/update this file).
Rewrite C++ part

RMID #55 Let the user choose output (either file or stdout).
RMID #56 Use stream class instead of hack "stuff" macro.
Update Object log method

RMID #56: YapLog object call with Macro is cleaner and dont add memory
leak.