MBS-5526: don't consider spaces right after the start of an <a> tag to count for diffing
MBS-5526: parse HTML outright, and keep tags fully together when tokenizing diffs, in a new method of Plugin::Diff
MBS-5526: DRY it up
Merge branch 'mbs-5526-html-diff' into beta

* mbs-5526-html-diff:
  MBS-5526: DRY it up
  MBS-5526: parse HTML outright, and keep tags fully together when tokenizing diffs, in a new method of Plugin::Diff
  MBS-5526: don't consider spaces right after the start of an <a> tag to count for diffing