UI: fix a few small regressions introduced with commit 3a67e72ef
UI: wrap up majority splash screen implementation

A couple TODO items remain including flushing out the
tips & screenshots content and setting the screenshot
img size but majority of logic is in place.

Tests have yet to be written for this component
UI: disable splash screen by default (for time being)
UI: small fix to ensure splash cycle started before stopping
UI: add mechanism to follow location w/ canvas camera
UI: focus on and follow planet on click