Adding expires returnExpiredItems property

[fishcharlie]

Summary:

This PR adds a new schema property to the expires object, returnExpiredItems.

Code sample:

Schema

const tokenSchema = new dynamoose.Schema({
	id: {
		type: String,
		required: true
	}
}, {
	timestamps: true,
	expires: {
		ttl: 3 * 60 * 60,
		attribute: 'ttl',
		returnExpiredItems: false // will not return expired items if false (default: true)
	}
});

Type (select 1):

• Bug fix
• Feature implementation
• Documentation improvement
• Testing improvement
• Test added to report bug (GitHub issue #--- @---)
• Something not listed here

Is this a breaking change? (select 1):

• 🚨 YES 🚨
• No
• I'm not sure

Is this ready to be merged into Dynamoose? (select 1):

• Yes
• No

Are all the tests currently passing on this PR? (select 1):

• Yes
• No

Other:

• I have searched through the GitHub pull requests to ensure this PR has not already been submitted
• I have updated the Dynamoose documentation (if required) given the changes I made
• I have added/updated the Dynamoose test cases (if required) given the changes I made
• I have run npm test from the root of the project directory to ensure all tests continue to pass
• I agree that all changes made in this pull request may be distributed and are made available in accordance with the Dynamoose license
• All of my commits and commit messages are detailed, explain what changes were made, and are easy to follow and understand
• I have confirmed that all my code changes are indented properly using 2 spaces
• I have filled out all fields above

[coveralls]

Pull Request Test Coverage Report for Build 636

• 10 of 11 (90.91%) changed or added relevant lines in 4 files are covered.
• 22 unchanged lines in 1 file lost coverage.
• Overall coverage increased (+0.6%) to 84.728%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
lib/Scan.js	3	4	75.0%

Files with Coverage Reduction	New Missed Lines	%
lib/Table.js	22	77.93%

Totals
Change from base Build 613:	0.6%
Covered Lines:	1846
Relevant Lines:	2108

---

💛 - Coveralls