sl-date-range-picker: "startDateValue" cannot be more than "endDateValue"

[juwara0]

Provide a fix for "startDateValue" is more than "endDateValue" and then verify the fix by turning the skipped test below back on.

This test fails: test( '"startDateValue" cannot be more than "endDateValue"', function( assert ) {

this.render( hbs`
    {{sl-date-range-picker
        startDateValue="09/25/2015"
        endDateValue="09/20/2015"
    }}
` );

assert.notEqual(
    this.$( '>:first-child' ).find( '.sl-daterange-start-date' ).find( 'input' ).val(),
    '09/25/2015',
    'The "startDateValue" is not more than the "endDateValue"'
);

});

[Yogeswar]

I'm working on this. addressed by #870 (will cause merge conflicts otherwise)

[SpikedKira]

Should be resolved by #1458