Add missing fields to files, folders, and web links

[carycheng]

No description provided.

[boxcla]

Hi @carycheng, thanks for the pull request. Before we can merge it, we need you to sign our Contributor License Agreement. You can do so electronically here: http://opensource.box.com/cla

Once you have signed, just add a comment to this pull request saying, "CLA signed". Thanks!

[coveralls]

Pull Request Test Coverage Report for Build 1917

• 28 of 30 (93.33%) changed or added relevant lines in 3 files are covered.
• 2 unchanged lines in 1 file lost coverage.
• Overall coverage increased (+0.2%) to 65.276%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/main/java/com/box/sdk/BoxItem.java	1	3	33.33%

Files with Coverage Reduction	New Missed Lines	%
src/main/java/com/box/sdk/BoxJSONResponse.java	2	93.33%

Totals
Change from base Build 1916:	0.2%
Covered Lines:	5288
Relevant Lines:	8101

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💛 - Coveralls