delete unused methods
implement delete(TaskUIFormat) method in ZombieStorage to support delete
tasks with same name, tag or location; and delete tasks at certain time
slot.
add mulitple Task delete functions for tag, name, location, time
Merge branch 'ZombieStorage' into mainlogic
edit false descriptors in delete commands
Merge remote-tracking branch 'origin/mainlogic'

Conflicts:
	src/interpreter/CommandSearchTag.java
	src/interpreter/Interpreter.java
changed search-name to search any task containing search string
updates:
- changed location character to '@'
- changed escape sequence to inverted commas
- allowed index range for delete in 2 formats (f1, f2 and f1-f5)
- allow flexible update by field - return commandAdd obj hasMissingArgs,
but with arguments intact, null/empty arraylist for unspecified fields