Reduced LRUCache size overshoot back to 0 from 100 as it caused heap
to grow too large.
changed the subsample to 2 so that map tiles consume less heap memory
Revert "changed the subsample to 2 so that map tiles consume less heap memory"

This reverts commit b5b08f40040f937f1a0d225537914b4715700466.
Merge pull request #1093 from crankycoder/features/1092-oom-maptiles

1092 reduce heap usage to prevent OOM