Added sleep function as mongo.sleep, using nanosleep
Added mongo.time
Added luarock spec
Updated rock spec
Updated readme
Removed compiler errors with clang
Modified indentation
Updated rockspeck
Merge pull request #30 from moai/develop

- Addition of `mongo.sleep` function, which allows to do nanosleep using C library.
- Addition of `mongo.time` with decimal resolution using C library.
- Minor changes to luarockspec and other compilation stuff.