Visual changes from design review

Made header 48px high.
QA:
- check the height of the main header
- check the Notifications and Help & feedback dropdowns are correctly positioned
- check the sticky headers in the sidebar are correctly positioned

Removed old items from environment header.
QA: The environment header should only have service and machine tabs.

Open unit details from charm name.
QA:
- drag a service to the canvas
- click deploy and confirm
- click on the service block
- click on the charm name below the service title (e.g. cs:precise/wordpress-22)
- the charm details should appear

Made inspector service icon larger
QA:
- drag a service to the canvas
- click deploy and confirm
- click on the service block
- the service icon should be 50x50px