updated example with simple cache implementation
Merge branch 'master' of github.com:Matt-Esch/surfacedb
Merge branch 'master' of github.com:Matt-Esch/surfacedb

* 'master' of github.com:Matt-Esch/surfacedb:
  updated example with simple cache implementation
update libs
Merge branch 'master' of github.com:Matt-Esch/surfacedb

* 'master' of github.com:Matt-Esch/surfacedb:
  update libs
commit generate terrain near edge
add cache + clip