1.8.3: Bug fixes and minor updates

• fixed a bug where the plugin would freeze for certain combinations of disabled/enabled dates; thanks Yogesh;
• fixed a bug where having two paired date picker with "direction" set to FALSE, the second date picker will not obey this rule once a date is selected in the first date picker; thanks Shane M;
• fixed a bug where when having paired date pickers, the "Today”" button was sometimes available although it shouldn't have been; thanks Matt;
• fixed some indenting issues and the scope of some variables; thanks W. van Kuipers;
• fixed a few minor issues reported by JSFiddle’s JSHint;
• minor update of source code regarding optimal usage of jQuery for creating the wrapper around the parent element;