Improved performance of encodeHash by 30%.
 * Removed the use of two arrays to keep track of min/max lat/long
 * Removed the StringBuilder, and managed that ourselves.

Ran multiple iterations of 100000000 encodeHash(..), on a Intel i7
        Before changes average of 4,298,333 hases per second.
        After changes average of 5,625,000 hashes per second, with less object creations.
Merge branch 'speed' of github.com:bramp/geo