Fix for mark command type

Wrong alias input.
Added more test cases for Parser
Test created for within period check

Refactored viewWithin period, fix, datePair != null, it can never be
null. //redundant code.
Add displaying id in viewAll and viewPeriod
Refactored date related test to DatePairTest

First commit
Merge branch 'master' into quality_control
Fix logic bug in DatePair.isWithinPeriod which happens when two dates are the same
Add tests for null dates in DatePair.isWithinPeriod