Update for devices with height < 500px

[coderwassananmol]

#3 Since, the MAX_HEIGHT is set to 500 by default, problems in the devices with less than 500px height will arise. So, in these devices there must be a workaround. I have added a check that verifies whether the MAX_HEIGHT is less than the window's height. If it is, then simply return the MAX_HEIGHT, else, return the window's height.

[StanleySathler]

Heyy @coderwassananmol
I'm really happy to see that you're feeling excited about contributing to your repository 🎉

In this commit, as far as I can see, you changed only dist/js/sth-select.js, which is gonna be lost when running $ gulp command again. 😛 Don't forget to change the src/js/_popup.js file and then generate the dist/js/sth-select.js using the Gulp.

Can I give you a little tip? Checking the line 119, in the file _popup.js, probably we should be considering - again - the filter's height.

[coderwassananmol]

I think we don't require filterHeight this time. Since we are focusing on the popupHeight on whole to resize it according to the window, considering filterHeight should not make much of a difference. Well, I will still try locally and let you know.