Before data was pulled first then written or read first and then pushed back

Only use 1 segment now but with multiple transfers

Source folder was removed if existed before but never recreated

Since the download of sources are performed in parallel, we cannot use
anymore a single log file.

The output of the download commands has been reduced to errrors only and
it will be outputted directly on stderr. Thus the log file stuff have been
completely removed.

Moreover the clonedeps function now takes the REPO as second parameter
and additional (non mandatory) git flags as fourth parameter.

Additional fixes have been introduced to run commands in script mode
(-q, -f, ...)

For dependencies in which a specific tags is specified we can download
the code snapshot instead of cloning the whole repo.

Perform all the download and git clone action in parallel using several
processes.

Due to the new parallel use of the clonedeps and wgetdeps functions,
some adjustment to printed message has been made. Now the function write
on stdout only once when they complete.

Use cmake in order to properly check and use both the Boost library and
the pthread one.

We need to be explicit about I/O as it cannot be simply repeated. A response
from the daemon will come eventually, either success or failure.

Previously, an ES was created for each destination in each read or write.
Creating and freeing these ES is costly. Also, these ESs had separate pools,
which is bad practice. Multiple ESs work on a single pool. The ABT_sched
decides which ULT or Tasklet is run by which ES at any time.

This change does also reduce CPU load as library IO RPC calls used CPU time
while waiting for the response.

daemon related cmake directives have been pushed into a standalon cmake
file into the src/daemon folder.

- 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.

The preload specific cmake files inherits the global flag declarations,
thus it is not necessary to specify again all the flags.
Moreover the only addition made by this declaration is the `-fPIC` flag.
According to the official CMake docs [1], is set automatically for
library target as SHARED. Thus we don't need to set it explicitely.

[1]: https://cmake.org/cmake/help/v3.6/prop_tgt/POSITION_INDEPENDENT_CODE.html

FILE_OFFSET_BITS flag was required for Fuse builds and is a remnant
from previous fs versions. Currently it is not required

Subprojects specific CMakeLists.txt inherits directives from the main cmake file.
Thus it is not necessary to replicate global level directives

since we use the `include_directories(include)` it is not necessary to
explitely specify all the headers file in the source list.

ADA-FS's statfs will fill the struct mostly with rough estimations.
It is not supposed to return accurate data but "some" data for applications to work

The specific version is necessary for local I/O to work.