WIP: Fix merge --no-ff

[IanLee1521]

Work in progress at fixing #83

So far I have fixed the short case, but broken the previous working case...

[hollenberry]

👋 @IanLee1521 ! Any luck with this since your last update? Just ran into the same bug myself while working on a demo.

[IanLee1521]

I haven't, not, but I need to circle back and resolve this and a few other issues. Would be happy to take help over at: https://github.com/ianlee1521/visualizing-git/tree/gh-83-merge-no-ff to try to get to a final working PR though!

[udovicic]

Changing this, and following lines with:

var branchStartCommit = this.getCommit(mergeTarget.id);
var base = (currentCommit.isNoFFCommit === true) ? currentCommit.parent2 : null;

while (branchStartCommit.parent !== base && branchStartCommit.parent !== currentCommit.id) {
  branchStartCommit = this.getCommit(branchStartCommit.parent);
}

will fix several issues, but unfortunately still does not work as expected in some edge cases. Hope this helps