Various adjustments to Sextant

+ Prevent wrapping in the back-to-top links
+ Add a nicer icon for those links
+ Broke scrolling behavior into its own module
+ Added another method to auto-invoke "close"ing to the Brenda module.
Bit fragile. We'll see.

Related to issue #10
Add 'addMessage' API and fix scrollTo on iOS

+ messages CSS
+ "Nag" addMessages script. Exposed via OSLC.addMessages
+ Introduce a fix for iOS where Sextant wouldn't scroll if you hit the
status bar

Related to issue #10