Fix retry logic

[sujaygarlanka]

Fix retry logic

• Retry for 400 invalid_grant error in authentication requests (Clock Skew)
• Honor Retry-After header if present by waiting for the time specified in the header before retrying
• Number of request retries after the initial request is now equal to the DEFAULT_MAX_ATTEMPTS config value

[coveralls]

Pull Request Test Coverage Report for Build 2174

• 43 of 60 (71.67%) changed or added relevant lines in 6 files are covered.
• 3 unchanged lines in 2 files lost coverage.
• Overall coverage increased (+0.05%) to 65.602%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/main/java/com/box/sdk/BoxDeveloperEditionAPIConnection.java	6	7	85.71%
src/main/java/com/box/sdk/BoxAPIRequest.java	21	24	87.5%
src/main/java/com/box/sdk/BoxGlobalSettings.java	3	6	50.0%
src/main/java/com/box/sdk/BoxAPIConnection.java	11	16	68.75%
src/main/java/com/box/sdk/SharedLinkAPIConnection.java	0	5	0.0%

Files with Coverage Reduction	New Missed Lines	%
src/main/java/com/box/sdk/SharedLinkAPIConnection.java	1	0%
src/main/java/com/box/sdk/BoxAPIRequest.java	2	65.38%

Totals
Change from base Build 2172:	0.05%
Covered Lines:	5527
Relevant Lines:	8425

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💛 - Coveralls