fix arrowheads joint scaling
Joint opacity needs to be set.
Rewrite arrowheads to be a function of head length
Merge branch 'master' into arrow-length
generalize spike to arbitrary angles
convert tails to be a function of length
added lengths travesal
fix haddock diagrams
more haddock diagram corrections
Allow semigroups-0.14
fixed documentation
small adjustments
Merge pull request #185 from diagrams/arrow-length

Arrow length
merge master
colorOfJoint