added media-query option

[jonex2]

Because matching heights sometimes should only work at a special viewport, i added a media query option.
example of using the option:
$('li').matchHeight({
byRow: false,
property: 'height',
target: null,
remove: false,
mq: "(min-width: 400px) and (max-width: 800px)"
});

[blackwood]

If anyone is waiting for this to pull request to be resolved, here's an alternative way you can achieve a similar result, by wrapping matchHeight's internal _update function with a conditional.

// caching jQuery selectors is neat!
var $top = $('.card__top')
var $inner = $('.subcard-inner, .subcard-alone-inner')
var $title = $('.card-absent-title-shim')

// init bound variable which indicates whether or not we've bound the elements.
var bound

function bindHeights() {
    $top.matchHeight()
    $inner.matchHeight({
      byRow: false
    })

    $title.matchHeight({
      target: $('.subcard__title')
    })
    // indicate that we've bound them.
    bound = true
}
// bind our necessary elements with their options.
bindHeights()

// preserve matchHeight's internal update fn
var __update = $.fn.matchHeight._update

// overwrite the function so that it does a conditional check
$.fn.matchHeight._update = function() {
    if (window.innerWidth < 700) {
        // if we are below our desired breakpoint, we can unbind and skip update
        if (bound) {
            $top.matchHeight({ remove: true })
            $inner.matchHeight({ remove: true })
            $title.matchHeight({ remove: true })
            // no need to unbind twice
            bound = false
        }
        return false
    } else {
        // only rebind if we need to again
        if (!bound) {
            bindHeights()
        }
        // call our preserved matchHeight fn
        __update()
    }
}

[matthewellishanson]

@blackwood Used your alternative approach and it worked great. Just one problem though: when I reduce my viewport size the matchheight removes as desired, but when I go back to the larger viewport those binds don't return to the matched heights they had originally at that browser size. Do you have any idea how to make it return the matched heights when you resize to the original viewport?