Adds WebDriverCache to reduce WebDriver startup shutdown cycles.
Use absolute times in limiter during job creation
Refactor SearchEngineJob
Remove accidentally commited return statement. Fix exceptions in job and add missing delay
Add checking STOP file and adjust default RateLimiter rate. Bumps version to 0.5.
Simplify JobRunner to avoid deadlocks. Initialize WebDriver only when job is executed. Bumps version to 0.6.