CREATE_CHECK_PARENTS controls if the existance of the parent node needs
to be checked during the creation of a child node.

Example: The check prevents the creation of file `/parent/child`
if `/parent` doesn't exists or if it is not a directory

By default CREATE_CHECK_PARENTS is enable and the check is enforced.
It can be disable to speedup creation operations by passing
`-DCREATE_CHECK_PARENTS:BOOL=OFF` as cmake parameter.

All paths underl /sys and /proc are forwarded to the kernel directly

 - Removed nested-if logic
 - Log all errors

The new `LOG_SYSCALLS` Cmake flag can be used to enable verbose logging of
system calls interception.

We don't want the log file to be created before command line parsing,
otherwise --version or --help cli option could not work beacause we
don't have permission to write to log file.

lseek was triggering a number overflow by converting long to integer on
its return value

Added specific lseek test

Write errors happenig on deamons are now reported back to clients.
"No space left on device" error is now properly propagated to clients.

Port is only meaningful for some of the communication protocols. For
instance psm2 is not using it at all.

Port can be still specified using the --listen,-l flag:

Example:
```
gkfs_daemon --listen "localhost:1234"
```

margo context id is not the id of the host that send the request. Is the
internal context id of local margo instance.

 - Use regular expression to parse lines
 - More consistent error handling
 - More comprehensive error messages

Implement proper error propagation and handling on get_dirents RPC.
Error happening on the deamon are now embedded on the returned response
and the client throws an exception once he receives the response.

CCI plugin have been tagged as deprecated in the Mercury library. We
where using it just for verbs, OFI+verbs can be used now as replecement.

Shared-memory communication can be disabled through cmake
compile time option `-DUSE_SHM:BOOL=OFF`

Refactored initialization code.

 - More detailed logging
 - Use exceptions to better propagate errors
 - Log signal type before shutdown