Tidy up includes and copyright notices, fix indentation

Tidy up includes and copyright notices, fix indentation

The files not mentioned in changelog below had only
copyright notices fixes and indentation fixes.

* defs.h: Include <stdint.h> and <inttypes.h>.
* file.c: Do not include <inttypes.h>.
Move struct kernel_dirent declaration below top include block.
* block.c: Do not include <stdint.h> and <inttypes.h>.
* quota.c: Likewise.
* desc.c: Likewise.
* signal.c: Likewise.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>