Disable text diffs by default

[Methuselah96]

Motivation

• diff-match-patch adds quite a bit to the bundle size, relative to jsondiffpatch. With diff-match-patch, the minified bundle size is ~33kB. Without it, the minified bundle size is ~14kB.
• Some people find the text diffs surprising, depending on what they're using jsondiffpatch for. There have been requests for an option to disable it altogether:
  • textDiff option set to "0" should allow single letters to be merged instead of taking the default value 60. #104
  • Invalid comparison result when the value contains more than 60 characters #248
  • Allow user to specify a maxLength for character diffing #263
  • Add option to opt out of text diffing #314

Breaking changes

• The main entry-point no longer includes text diffing by default. Users must either pass in the diff-match-patch library in as a property of the textDiff option, or use the jsondiffpatch/with-text-diffs entry point that is included for convenience.
• The textDiff option now has a required diffMatchPatch property.