fix(cli): Always pass an instance of fs to processArgs.

Closes #677
fix(init): set default filename

Since d4a06f296c4d805f2dccd85b4898766593af4d66, the config file is set only if it exists, but `karma init` requires the filename to be set. This sets the filename to `karma.conf.js` if not present.

Closes #680
Closes #681
chore: update contributors
chore: release v0.10.1
test(e2e): add test that uses browserstack
chore: update homepage link in package.json
test(e2e): Add basic cucumber setup for better e2e testing.