bootstrap navbar 100 width

You could get the width of the navbar to go the full length of the page by making the container inherit from ".navbar-wrapper". You may also want to get rid of the padding you have set in ".navbar-wrapper .navbar"

The following styles worked for me: See codpen: http://codepen.io/JordanLittell/pen/wadWxv

/* Special class on .container surrounding .navbar, used for positioning it into place. */

.navbar-wrapper {
    position: absolute;
    top: 0;
    right: 0;
    width: 100% !important;
    left: 0;
    z-index: 20;
}

/* Flip around the padding for proper display in narrow viewports */
.navbar-wrapper > .container {
    padding-right: 0;
    padding-left: 0;
    width: inherit;
}

.navbar-wrapper .navbar {
    width: 100% !important;
}

.navbar-inverse {
  width: 100% !important;
    background-color: rgba(0, 0, 0, 0.5) !important;
  border-radius: 0;
}

.navbar-inverse .nav > li > a {
    color: #FFFFFF;
}

.navbar-inverse .nav > li > a:hover {
    background: none;
}

.navbar-brand a {
    color: #FFFFFF;
}

.main-header-background {
    background-size: 100% 100%;
    background-repeat: no-repeat;
    background-position: center; 
    background-image: url('http://www.riwakawebsitedesigns.com/external/images/stars/img-stars-2.jpg');
  height: 620px;
  width: 100%;
  margin-bottom: 60px;
}