Cleanup and added notes for further improvements.
Fixed typo expected_durartion. Duration was never actually checked.
Cleanup test.js.
Fixed wrong expected_duration. Now all tests are passing.
Refactoring. Cleanup.
This conforms to original specification, which allow `Mon Md-Mon Md' ranges
Revent change of variable name

It's no longer `start of this year' after the second line, so using
such variable name would be misleading.
Remove extra space
Merge branch 'ypid-master-merge'

This merges master branch of ypid fork, with some minor rollbacks
from me.