Retrieving unmasked value

This patch allows to get the unmasked value of an input resolving the issue #97.

**1. Why is this change necessary?**
Plugins like this, who format an input in a WYSIWYG way, have a specific audience: developers who care about usability. In the case of this particular type of plugin, we want that the user can insert a monetary value without worrying whether he should/can use a period, comma, etc, and we want he can be able to see smoothly the results as he type. This is what maskMoney does, but this is just a part of the process. 

The natural flow is: 
a) use some formatter (like maskMoney) to improve the user's usability and experience. 
b) unformat the result 
c) save to some database. 

To make any processing with the value we have to remove the format. So its natural for who make use of a plugin like this to write some code to remove the format and extract the pure data. If this is the natural use, why not add this functionality?

**2. How does it address the issue?**
I added a new method called _unmasked()_ encapsuled within the maskMoney methods. 
By calling _myinput.maskMoney('unmasked')_ will return a float object with something like _1234.56_.

**3. What side effects does this change have?**
None I believe. It's backward compatible.