complete Makefile with git-flow compliance

Signed-off-by: Sebastien Varrette <sebastien.varrette@uni.lu>
add VERSION file

Signed-off-by: Sebastien Varrette <sebastien.varrette@uni.lu>
Merge branch 'release/1.0.0-b50'

* release/1.0.0-b50:
  add VERSION file