Add observers for stylesheet mutations (#177)

* hack together stylesheet observer

* Add test coverage for insertRule/deleteRule on stylesheets

* Add new observers

* update patch based on changes to master

* Functioning event recording

* Remove print statements

* Fix ID usage and mark add vs remove

* Correct type

Co-authored-by: Jon Perl <perl.jonathan@gmail.com>

package.json

@@ -4,6 +4,7 @@
   "description": "record and replay the web",
   "scripts": {
     "test": "npm run bundle:browser && cross-env TS_NODE_CACHE=false TS_NODE_FILES=true mocha -r ts-node/register test/**/*.test.ts",
+    "test:watch": "PUPPETEER_HEADLESS=true npm run test -- --watch --watch-extensions js,ts",
     "repl": "npm run bundle:browser && cross-env TS_NODE_CACHE=false TS_NODE_FILES=true ts-node scripts/repl.ts",
     "bundle:browser": "cross-env BROWSER_ONLY=true rollup --config",
     "bundle": "rollup --config",