rough refactoring to make code clearer
debug file listing and improve performance

put unicode everywhere it's possible
make least possible requests to database
debug file writing
add tests for fuse client
clean binary cache code

* add comments
* save file size on file creation for both case (with or without data given).
clean dbutils module

* add comments
* remove useless operation
clean couchmount module

* add comments
* improve caching
refactoring

* move path helpers in a separate module
* use ntpath to split path instead of home made method
fix wrong calls
fix attr cache retrieval
add unlink test
add directory tests
fix writing bugs
fix rmdir + reorganize func order
update cached file size on writing
manage rdwrite case
minor refactoring of open function
Merge branch 'better-writes'