Reduce complexity

[oliverfoster]

extension to #122

Fix

• Simplified relative container positioning (Change from fixed to absolute, put annotation in correct parent)
• Simplified event attachment (No need to popup checking as dom modifier does that, switch to animation/transition end)
• Reduced recalculations (Chained isVisible, isReadable in &&, so that they only happen when the other fails)
• Reduced dom modifications (Added hashing for previous vs next state)
• Reduced duplicate functionality and clarified (shouldAnnotate, isVisible, etc)
• Add fix for nav buttons, where their small + hard-top nature makes for annotation positioning issues.

[kirsty-hames]

Noice @oliverfoster - works as expected thanks 👍