Update Travis CI Node.js versions (0.8, 0.10, 0.11).

https://code.google.com/p/esprima/issues/detail?id=317
[ES6] Pattern params default values

Per latest ES6 draft [1], function parameters that are destructuring patterns
may have default values. This diff allows parsing `AssignmentExpression`
that follows the pattern and `=`.

See tests attached for details.

[1] https://people.mozilla.org/~jorendorff/es6-draft.html#sec-function-definitions

```
FormalParameter : BindingElement

BindingElement : BindingPattern Initializer[opt]
```

https://code.google.com/p/esprima/issues/detail?id=555
[ES6] Computed properties

Per ES6 spec [1], Object Initializers may have computed properties.

Grammar:

```
ComputedPropertyName[Yield] :
  [ AssignmentExpression[In, ?Yield] ]
```

Examples:

```
var x = 'y';
var foo = {[x]: 10};
console.log(foo); // {y: 10}
```

More complex `AssignmentExpression`:

```
var y = 'y';
({['x' + y]}).xy; // 10
```

Methods and accessors:

```
var foo = {
  [dynamicMethodName]: function() {},
  [conciseMethod]() {},
  *[generatorName]() {},
  get [foo]() {},
  set [foo](v) {}
};
```

In destructuring assignment:

```
var x = 'y';
var {[x]: y} = {y: 10};
console.log(y); // 10
```

Issue #480: https://code.google.com/p/esprima/issues/detail?id=480

[1] http://people.mozilla.org/~jorendorff/es6-draft.html#sec-object-initializer
Merge remote-tracking branch 'ariya/harmony' into fb-harmony
Update tests to account for computed properties

Originally added in 2bb17ef9a45c88e82d72c2c61b7b7af93caef028
Fix version numbers

dda408c0054fbd33ff8b724816983b69f1c56cb0 bumped the least significant
digit, which is reserved for upstream changes (or rather the last
3 digits are reserved for upstream). Version changes exclusive to
fb-harmony should be on the preceding digits.