*
@method toNumber([base] = 10)
@returns Number
@short Converts the string into a number.
@extra Any value with a "." fill be converted to a floating point value, otherwise an integer.
@example

'153'.toNumber()    -> 153
'12,000'.toNumber() -> 12000
'10px'.toNumber()   -> 10
'ff'.toNumber(16)   -> 255

*
function(base) {
      var str = this.replace(/,/g, '');
      return str.match(/\./) ? parseFloat(str) : parseInt(str, base || 10);
    }