Minify_YUICompressor: add support for increasing stack size

yui compressor can sometimes run out of stack, internet suggests to increase stack size. so this is what i did.

    $ yuicompressor test.css 
    Exception in thread "main" java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at com.yahoo.platform.yui.compressor.Bootstrap.main(Bootstrap.java:21)
    Caused by: java.lang.StackOverflowError
    ...

css itself that causes this, is pretty simple:

    /* stack overflow test */
    div.image {
	    width:            100px;
	    height:           100px;
	    background-image: url('data:image/png;base64,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');
    }

to increase stack size, pass it to `$options`:

        $options = array(
            'stack-size' => '2m',
        );
        $minOutput = Minify_YUICompressor::minifyCss($src, $options);