re-initializing should update settings

[olleicua]

for example if a monthpicker is already set up with:

$('#custom_widget').monthpicker({
    pattern: 'yyyy-mm',
    selectedYear: 2010,
    startYear: 2008,
    finalYear: 2012
});

then it should be possible to update the finalYear property with:

$('#custom_widget').monthpicker({finalYear: 2012});

[olleicua]

ignore bbf285f use https://github.com/lucianocosta/jquery.mtz.monthpicker/pull/48