Merge pull request #171 from mulesoft/features/make-console-section-resizeable-61490090

Visual and behavioral bug fixes
Pointing at patched version of raml-grammar for testing fix.
Fix usemin task to look for images in proper place

  - use "assetsDirs" option instead of "dirs" as it does not exist for
    usemin
  - move *.css files outside of styles/css directory as there is no
    other way to use relative paths for images and make it all work
    together (less -> css -> images)
Add menu bar between header and content
Added webkit flex css properties.
Added webkit compatible flex css properties.
Merge branch 'file_browser_bar' into features/make-console-section-resizeable-61490090