Added About modal with last commit hash, moved some dialogs to lesionTracker package from viewerbase (OHIF-52)

Packages/design/styles/common/global.styl

@@ -29,3 +29,13 @@ html hr
   -moz-user-select: none
   -ms-user-select: none
   user-select: none
+
+.modal-dialog
+  .modal-content
+    background: $primaryBackgroundColor
+    border-color: $uiBorderColor
+    color: $textSecondaryColor
+
+    .modal-header, .modal-footer
+      border-color: $uiBorderColor
+