(backends) Delete useless methods from AbstractBackend

Also delete useless calls in concrete backends
(OrccUtil) Remove useless files utils methods
(OrccUtil) Remove useless function createFolder
(OrccUtil) Remove other methods related to files management
(backends) Delete useless constructors from printers

Now almost all printers can be instanciated without parameter. The option
map and important objects are passed later, so a printer instance can be
reused multiple times within a backend
(misc) Fix possible issues and various errors

Found with FindBugs
(backends) Remove 1 TODO and 1 FIXME from AbstractBackend
Merge branch 'clean_useless_code_from_backend'