use correct quaternion

* fixes celestial north pole to be actually rendered
reduce scope of local variables
no need for outer if-statement
take planetId into account for signal connection/disconnection
use Planet::epsilon() rather than hardcoded value
tools/gen-sat-catalog: Log info when writing catalog
Fixed several invalid encoding characters' compiler warnings
fix link for tagged translations
always keep level-zero tiles in the hash
wip: asynchronous tile loading

FIXME: tile update issues when changing map theme