v4.3.0

Bug Fixes

• build: switch from yarn to package-lock.json (#3351) (6c5add2)
• config: Simpilfy error proceesing. (#3345) (582a406), closes #3339
• deps: lodash update. (#3341) (5614c04)
• server: Simplify 'dom' inclusion. (#3356) (5f13e11)
• test: test:client silently failing on Travis (#3343) (1489e9a), closes /travis-ci.org/karma-runner/karma/jobs/537027667#L1046
• travis: Pin to trusty (#3347) (1c6c690)

Features

• async: frameworks can be loaded asynchronously (#3297) (177e2ef), closes #851
• config: socket.io server pingTimeout config option. (#3355) (817fbbd)
• preprocessor: preprocessor_priority execution order. (#3303) (c5f3560)
• runner: feat(runner): (62d4c5a), closes #2121 #2799 #2121 #2799