Add responsiveness for footer. Update gulpjs, package.json and bootstrap sass

static/assets/bootstrap/sass/_progress.sass

@@ -0,0 +1,37 @@
+@keyframes progress-bar-stripes
+  from
+    background-position: $progress-height 0
+
+  to
+    background-position: 0 0
+
+.progress
+  display: flex
+  height: $progress-height
+  overflow: hidden
+
+  // force rounded corners by cropping it
+  font-size: $progress-font-size
+  background-color: $progress-bg
+
+  +border-radius($progress-border-radius)
+  +box-shadow($progress-box-shadow)
+
+.progress-bar
+  display: flex
+  flex-direction: column
+  justify-content: center
+  color: $progress-bar-color
+  text-align: center
+  white-space: nowrap
+  background-color: $progress-bar-bg
+
+  +transition($progress-bar-transition)
+
+.progress-bar-striped
+  +gradient-striped
+
+  background-size: $progress-height $progress-height
+
+.progress-bar-animated
+  animation: progress-bar-stripes $progress-bar-animation-timing