New functions for gen_valid.py.
New functions for gen_valid.py.

  - svalid_integer: Improved this to work on hex values.
  - svalid_dir_path:  New function.
  - valid_dir_path:  New function.
  - svalid_file_path:  New function.
  - valid_file_path:  New function.

Change-Id: If990bed0c202651b07cbf86d5c0873827ba4143c
Signed-off-by: Michael Walsh <10404802c7de463f402c4a18638106ca1b12ef61@us.ibm.com>

openbmc/openbmc-test-automation,openbmc/openbmc-test-automation