* AddressBookParser.java: add in archive command
CliSyntax.java: add in PREFIX_DATE
ParserUtil.java: add in parseDate method
Model.java: add in archiveJob method
Date.java: add in constraints, regex test and new constructor
ArchiveCommand.java: created archive command
ArchiveCommandParser.java: created parser for archive command
DateRange.java: create DateRange object for archive command

* ModelManager.java: Add in archiveJob method

* Date.java: changed date format, included methods to getDay, getMonth, getYear
DateRange.java: add in compareTo method

* ArchiveCommand.java: change date prefix and remove extend to UndoableCommand
CommandWords.java: include in archive command
ArchiveCommandParser.java: change date prefix
CliSyntax.java: change date prefix and removed address prefix
AddressBook.java: implement archiveJob method
Date.java: change date format and date regex

* AddressBook.java: change job iterator

* MainApp.java: included archiveJobStorage and updated StorageManager constructor call
AddressBook.java: add getArchiveJobList method
ReadOnlyAddressBook.java: add abstract method of getArchiveJobList method
UserPrefs.java: included archiveJobFilePath
Storage.java: add abstract method of getArchiveJobPath, readArchiveJob and saveArchiveJob
StorageManager.java: updated StorageManager constructor to include ArchiveJobStorage, implemented getArchiveFilePath, readArchiveJob and saveArchiveJob
XmlFileStorage.java: add saveDataToFile and loadDataFromArchiveFile method
ArchiveJobStorage.java: interface to access archive data
XmlArchiveJobStorage.java: implement ArchiveJobStorage interface to access archive data
XmlSerializableArchiveJob.java: serialise archive job entries into xml file

* Updated test files

* FileUtil.java: add in createEvenIfExist method
AddressBook.java: create a new archiveJob list everytime the command is called
XmlArchiveJobStorage.java: replace createIfMissing method with createEvenIfExist method
Fix checkstyles

* Fix checkstyle

* Fix checkstyle

* Fix checkstyle

* Revert changes for Date.java
Fix checkstyle

* Changed format of Date
Minor edit