Add toast component documentation

- Add documentation that describes when and how to use a toast message
with code snippets
- Add an informational toast method in the BVToastMixin
- Add BVToastMixin to enhaceApp to register mixin globally.

Signed-off-by: Derick Montague <derick.montague@ibm.com>
Change-Id: I89bf2aa8b3fdb9294354a80c98ccf692b6e3615a
diff --git a/src/assets/styles/_toast.scss b/src/assets/styles/_toast.scss
index 538f996..9295b17 100644
--- a/src/assets/styles/_toast.scss
+++ b/src/assets/styles/_toast.scss
@@ -4,7 +4,7 @@
 
 .toast {
   padding: $spacer/2 $spacer/2 $spacer/2 $spacer;
-  border-width: 0 0 0 5px;
+  border-width: 0 0 0 3px;
   .close {
     font-weight: 300;
     opacity: 1;
@@ -25,12 +25,20 @@
 
 .b-toast-success .toast {
   border-left-color: $success!important;
+  background-color: $success-light;
+}
+
+.b-toast-info .toast {
+  border-left-color: $info!important;
+  background-color: $info-light;
 }
 
 .b-toast-danger .toast {
   border-left-color: $danger!important;
+  background-color: $danger-light;
 }
 
 .b-toast-warning .toast {
   border-left-color: $warning!important;
+  background-color: $warning-light;
 }
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