Refresh functionality

[ChrisDoernen]

Hi there,

I like your plugin very much and have thus used it for a new website recently. In testing we found that if there is caching enabled either client or server side, the user might be confused when he likes the page and the value jumps to the actual like count skipping a few values.

I thought it was a good idea to add a refresh when the page is loaded in the first time, not affecting the counting mechanism. If you like it, feel free to merge the changes.

Again, thank you for sharing this!

All the best, Chris