Fixing a trivial bug in starblocklist.cpp that was preventing markNext() from being called. This was causing blocks to never be inserted into the LRU Cache, and thus, cached blocks were never reused.

With this fix, we achieve a 2x drop in memory usage when limiting magnitudes at zoom in and zoom out are 10.0 and 6.2!

Leaving the debug statements till we are sure of the code quality.