Fixed objects being sometimes not able to be stored statically in a block when block has been unloaded

New map generator added (and SQLite, messed up the commits at that time...) (import from temporary git repo)

Moved some mapnode content stuff from mapnode.{h,cpp} and digging property stuff from material.cpp to content_mapnode.{h,cpp}

Reduced server CPU usage on NodeMetadata step()s. Also furnace now cooks while no players are near it.

--HG--
extra : rebase_source : 8ad4d13fc7ab1088ebd18cf968d912949aab8eae

--HG--
extra : rebase_source : 7260636295d9068fbeeddf4143c89f2b8a91446c

Modified block mesh generation to have clearer input and output. Instead of being a messy object oriented cludge, it now is a messy cludge with separate parameters.

fixed a possible infinite loop in ClientEnvironment (dtime counter getting so small that it doesn't increment the value)

--HG--
rename : data/luaobjects/test/client.lua => data/scripts/objects/test/client.lua
rename : data/luaobjects/test/server.lua => data/scripts/objects/test/server.lua