Fix GhostTab and GhostTabPane array dependencies

No issue
- TabPanes weren't finding their tab due to not listing all their dependencies in Ember.computed
Merge pull request #4132 from novaugust/fix-tab-pane-connection

Fix GhostTab and GhostTabPane array dependencies
Fix relative em sizing bug
Fixes hidden scrollbar.

fixes #4194
- Remove relative positioning
Merge pull request #4195 from halfdan/4194-scroll

Fixes hidden scrollbar.
Allow scroll on setup form
Fix notifications being cur off on auth/setup screens
Prevent horizontal scrolling in the PSM
Merge pull request #4197 from PaulAdamDavis/minor-052-bugs

[WIP] Fix minor styling bugs