add POST support

[ccloquet]

I added the ajax POST support with

switch(settings.ajax_type.toLowerCase())
{
    case 'post':
    $.post(settings.source, settings.ajax_params, function (jsData) {
            element.data = jsData;
            core.init(element);
        }, 'json')
    break;
    case 'get':
        $.getJSON(settings.source, function (jsData) {
            element.data = jsData;
            core.init(element);
        });
}

in the core.create function.

Then I added the following defaults settings

ajax_type: "get",    
ajax_params: {},    

[usmonster]

Thanks for the contribution, @ccloquet! I don't think this is a common enough use case to include in the plugin, so I'll close it for now. We can reopen later it if there's more feedback or requests for such behavior.

Thanks again!