Implement archive feature

[jroberts91]

No description provided.

[coveralls]

Pull Request Test Coverage Report for Build 426

• 105 of 187 (56.15%) changed or added relevant lines in 15 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-2.8%) to 90.533%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/main/java/seedu/address/MainApp.java	5	7	71.43%
src/main/java/seedu/address/model/UserPrefs.java	2	4	50.0%
src/main/java/seedu/address/storage/StorageManager.java	13	16	81.25%
src/main/java/seedu/address/storage/XmlFileStorage.java	4	8	50.0%
src/main/java/seedu/address/commons/events/ui/ListPickerSelectionChangedEvent.java	0	5	0.0%
src/main/java/seedu/address/storage/XmlArchiveListStorage.java	16	22	72.73%
src/main/java/seedu/address/storage/XmlSerializableArchiveList.java	13	19	68.42%
src/main/java/seedu/address/ui/ListPicker.java	6	14	42.86%
src/main/java/seedu/address/ui/MainWindow.java	4	12	33.33%
src/main/java/seedu/address/model/ArchiveList.java	15	24	62.5%

Totals
Change from base Build 395:	-2.8%
Covered Lines:	2257
Relevant Lines:	2493

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💛 - Coveralls

[jroberts91]

see #114