doc: added image to README
fix: properly format errors without data

Fixes #38
Closes #39
chore: update contributors
chore: release v0.2.9
chore(package.json): update sauce-connect-launcher to v0.5.1

A few releases have passed since this was last upgraded, it would be good to keep this up to date with
the live service it works against.
chore(package.json): update sauce-connect-launcher to v0.6.0

Closes #47
chore: use latest web driver (wd package)

Bump wd from version 0.2.12 to 0.3.4.

Closes #51
fix: avoid failrues on error message formatting

Fixes #46

Closes #48
fix: override env vars with explicit config vars

Closes #50
chore: update contributors
chore: release v0.2.10
docs: document connectOptions

Closes #52
chore: added sample sauceConnect options
chore: use progress reporter to see more output