tools: pmempool utility

- pmempool utility with the following commands:
-- create - creating pool files
-- info - parsing pool files
-- dump - dumping data from pool files
-- check - checking and repairing pool files
- update scripts for creating packages
- bash completion script
- manual pages and README file
This function checks the consistency of pmemblk header. The only one filed in this header is considered as persistent - block size. Since we don't have a checksum for this field the only way we can validate this field is to compare its value with the external_lbasize value from BTT info header - these values should be equal. I look for the first valid BTT Info in order to get the reliable value for comparison. The invalid BTT means that the pool is corrupted but this can be recovered from BTT Info backup. If all BTT infos are invalid it means the BTT layout is not written yet.