Merge remote-tracking branch 'raniere/free-format'
Merge remote-tracking branch 'raniere/keys'
Merge remote-tracking branch 'raniere/pgfcomp'
Merge pull request #41 from r-gaia-cs/rename

Update README
Merge raniere/tau and fix empty tau
Merge raniere/labels first commit
Fix bug when count the number of problem solving

Some solvers can save the time spending solve the problem as 0.0
and this will break the scale due a division by zero. We solve
this problem using a regex to check if the time is zero and if it
was adding a epsilon.
Raise error if time spending is zero