For some comunication layers an out of band communication is required for putting in place the specific protocol handshake.

In those case a shared lookup file could be used to distribute deamon's endpoints information to all the clients.

This file need to resides on a shared filesystem and can be specified using the new CLI parameter `--lookup-file`.

gid and uid metadata fields have never been used and can be removed
safely

the functionality wasn't used at all and it will be implemented later
with a different approach

Data operation has been grouped under a ChunkStorage class
that will manage all the data backend operations.

The instance of this object is stored into the ADAFS_DATA sigleton.

Review and fixes that died when rebasing all commits

Nafi3 authored Mar 12, 2018 and Marc Vef committed Mar 23, 2018

This commit gives new options regarding separation of metadir and rootdir location. If only rootdir destination is given both metadata and data is stored at the same path

- Previously the directory hierarchy was not clear regarding to which
  file belong to which part of the project (client or daemon).
  Further, we will have other clients in the future (such as Fuse).
- CMake files now differentiate between include dirs for all targets
  and target specific ones.
- Removed duplicate -pg flag.
- Not listing header files when adding executables or libraries
  is considered bad practice. Note that include_directories() is adding
  include paths to the code while adding all files used for executables
  and libraries provide the context which files belong to each binary.
  When only include_directories() is set, CMake assumes that all files
  belong to a binary (which is not necessarily true). As a result,
  some IDEs may break as the do not support this assumption.

  In general we should almost always favor explicitness over implicitness.

Private data of fuse is still used for inode and will be moved later to the singleton.