Merge remote-tracking branch 'origin/parser/Victor' into logic/wenhao
parser will now check to ensure time is valid
Fix Search Handler return type bug
properly rejects when user inputs both time range and deadline
fixed undo command
Merge commit 'c4cc167d5df68ab7f656fd61dd1175d86b910550' into parser/Victor
Merge branch 'ui/victor' into parser/Victor
Fixed bug with error printing out two new lines
refactored code
Slight changes to error messages
updates test cases to reflect new error messages
Fix command type problem in search
Merge remote-tracking branch 'origin/ui/victor'
Merge remote-tracking branch 'origin/parser/Victor'
Merge remote-tracking branch 'origin/logic/wenhao'