Draw loops

[flo-dup]

Please check if the PR fulfills these requirements

• The commit message follows our guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

Does this PR already have an issue describing the problem ?
Yes fixes #28

What kind of change does this PR introduce?
Feature / bug fix

Does this PR introduce a breaking change or deprecate an API? Yes

• The Breaking Change or Deprecated label has been added
• The migration guide has been updated in the github wiki (What changes might users need to make in their application due to this PR?)

Other information:
Loops are placed between non-loop edges if enough place, one in each interval if possible. If not the circle is divided in nbLoops part, starting in the middle of the largest interval. Loop aperture can be changed in SvgParameters. See for instance the 3 different cases in the unit tests:

• Loop aperture = 60°, enough place to put each loop in a separated interval:
  

• Loop aperture = 80°, not enough place to put loops in separated intervals, but enough place in the largest interval to put them all:
  

• Loop aperture = 100°, not enough place in the intervals, therefore dividing the circle in 2, starting in the middle of the largest interval: