Round paddings of .container & .container-fluid to match .row's margins

Created by: studyjan

When i use @grid-gutter-width: 15px; .container-fixed will generate:

.container {
    padding-left:  7.5px;
    padding-right: 7.5px;
    ...
}
.container-fluid {
    padding-left:  7.5px;
    padding-right: 7.5px;
    ...
}

but .row has bad negative margin:

.row {
    margin-left: -7px;
    margin-right: -8px;
}