Address internationalization issues.
implements nand
readme grammar for nand
Example for #447
Added any.label method
Switched from using language.root to language.label
fix #454 : handle 0 and null arguments
Add test for #456
Enable to pass "now" in date.min and date.max

It is not currently possible to validate a date relatively to the
current time. For example, the following schema will always validate
relatively to the time of the `schema` object allocation:

```javascript
var schema = {
  date: Joi.date().min(new Date())
};
```

This patch addresses this issue by adding a new `'now'` placeholder.
It dynamically computes the current time on-the-fly at each comparison.
Allowing to always compare relatively to the current time.

```javascript
var schema = {
  // Ensure the date field cannot represent a past date
  date: Joi.date().min('now')
};
```
Upgrade to lab 5.x

Fixes #476.
Retain object reference when no rules specified
Merge pull request #478 from hapijs/object-shortcut

Retain object reference when no rules specified
Added test that proves that integers as strings are okay but negative integers are not working.
Fix for negative date numbers
4.8.0
Document object.keys extending schema.

Original wording just said that it sets the allowed keys, but it can also "extend" an object.
Merge pull request #479 from tuhoojabotti/master

Document object.keys extending schema.
Fix #480 - Compute 'now' on validation
4.8.1
Enable node 0.11 builds