Add sort and direction fields to search

[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 1837

• 8 of 12 (66.67%) changed or added relevant lines in 1 file are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage increased (+0.07%) to 61.373%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/main/java/com/box/sdk/BoxSearchParameters.java	8	12	66.67%

Files with Coverage Reduction	New Missed Lines	%
src/main/java/com/box/sdk/BoxSearchParameters.java	1	68.6%

Totals
Change from base Build 1835:	0.07%
Covered Lines:	4908
Relevant Lines:	7997

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💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 1840

• 12 of 12 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.2%) to 61.536%

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Totals
Change from base Build 1835:	0.2%
Covered Lines:	4921
Relevant Lines:	7997

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💛 - Coveralls