Ported over Postal-Code Lookup

Also, added tests for Postal-Code Lookup.
Added some more test cases for Postal-Code Lookup
Updated documentation to reflect the addition of Postal Code lookup
Now, returing a RegExp rather than a String for Postal-Code regex lookup. Also, fixed typos in the documentation.
Updated the documentation and fixed some typos that had crept in.
Fixed the timezone bug in DateTimeFormatter.

The function returned inaccurate results for timezones that weren’t
offset from GMT in multiples of complete hours (for example, +5:30 or
+5:45). By adding a Math.floor to the calculation of the hours in the
offset, this can be fixed. Using Math.floor effectively converts the
division operation into an integer division which returns an integer.
This fixes the subsequent calculation error that led to the wrong
timezone being returned.
refactored the PostalCodes class to fix scoping issues.
Merge pull request #30 from radzinzki/master

Ported over the Postal-Code Lookup functionality.