v0.31.3

Fixes

• Properly name more shim functions
• Fix an IE bug where the layout engine internally calls the userland Object.getOwnPropertyNames (#333)
• Ensure Map.prototype[Symbol.iterator] === Map.prototype.entries
• Ensure Set.prototype[Symbol.iterator] === Set.prototype.values

Security/Robustness

• - Cache more native methods in case they're overwritten later

Performance

• Add more Map/Set fast paths for more primitives: boolean, null, undefined

Tests

• Object.assign pending exceptions: IE 9 preventExtensions doesn't throw, even in strict mode
• IE 11 has native Map/Set, but it takes an optional function, not an optional iterable, in the constructor
• Add more "exists" early bailouts, to declutter native test results
• Test up to io.js v2.2

Docs

• Alphabetize shim lists in the README

Dependencies

• Update mocha, es5-shim, uglify-js, jshint

Refactoring

• Style cleanups