use Object.defineProperty to provide a Symbol.create impl, instead of an assignment.  fixes #161
Fixed an ES5 strict test that crashes in Chrome

The test `(function f() { f = 123; })()` actually throws a SyntaxError
on evaluation, not a TypeError on execution, in the current Chrome. I'm
really not sure which is fully correct for either the ES5 or ES6 specs.
Nevertheless, I've changed that line to be eval()ed so that the entire
script doesn't crash.

Also, the link to the strict mode page is fixed.
Merge pull request #196 from webbedspace/strictmode

Fixed an ES5 strict test that crashes in Chrome
Merge pull request #163 from toshok/Symbol.create-fix

use Object.defineProperty to provide a Symbol.create impl.  fixes #161
Build html files
Add exponentiation operator to ES7 table. Closes #179
ES6: Added tests for each Proxy handler

This adds tests for the Proxy get, set, has, deleteProperty,
getOwnPropertyDescriptor, defineProperty, getPrototypeOf,
setPrototypeOf, isExtensible, preventExtensions, enumerate, ownKeys,
apply and construct handlers.
EJS support is inferred from the source.

Also fixes a few other results for old Firefox versions.

Sorry that this diff looks terrible, but if you run `git diff
--minimal`, it more accurately reflects the changes.
Added missing property names to the Reflect test
Added a Proxy.revocable test
Updated Proxy tests to multi-line comment strings

NOTE: this commit only updates data-es6.js.