Tests with redundant/inefficient cron expressions
Tests with redundant/inefficient cron expressions

Add new unittest cases with real-world examples of poorly written cron
expressions created by end-users (who aren't cron experts).  Specific
optimizations opportunities include:
- Range reduction:  Minutes of 0-59 can be replaced with "*".
- Removal of duplicate values: Hours of 4,1-4,5,4 can be simplified to 1-5

kiorky/croniter,kiorky/croniter