chore(readme): update Bootstrap CSS inclusion example

This commit fixes README example of including Bootstrap dependency
in generated project in that way that Bootstrap CSS dependency is
moved up - to be the first in build bundle.
The reason behind this change is that Bootstrap comes with reset
CSS code and globals that are intended to be global unless reset
and changed by cascading file - here style.css.
Thanks!

Close angular#2197

Author: peterblazejewicz

README.md

@@ -370,8 +370,8 @@ Then add the needed script files to `apps[0].scripts`:
 Finally add the Bootstrap CSS to the `apps[0].styles` array:
 ```
 "styles": [
-  "styles.css",
-  "../node_modules/bootstrap/dist/css/bootstrap.css"
+  "../node_modules/bootstrap/dist/css/bootstrap.css",
+  "styles.css"
 ],
 ```