In type annotations generated by the WizPass, make the types non-nullable.

Also update the Wiz codebase to match.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=82551596
Mark the checkRequires option as deprecated. Users should pass --jscomp_{error,warning}=missingRequire instead.

This also ensures that --jscomp_{error,warning}=missingRequire will work as expected.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=82552162
Eliminate redundant flush() before close() calls
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=82660149
Warn for unions like "{string|?}" which is actually just equivalent to "{?}"
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=82661521