returns correct time if only minutes changed
returns correct time if end time is an even hour--not accounting for period change
time correctly changes period once
accounts for roll over hours when changing periods
refactor before next test
accounts for when end time changes hours and periods
accounts for when changing multiple days without changing periods
fix logic error with roll over hours
refactor for readability
add extra space for clarity of logic
add example usage case
Merge pull request #1 from anniesing/implement-add-time

Implement add time