src/journal.c: Fix mismatched comparison
src/: Use a #define, `lua_pushuint64` to push unsigned 64 bit numbers.

For now, I've defined it as lua_pushnumber, as that's as good as you'll get with standard lua.
Once 5.3 is out, this can be changed to a check against LUA_VERSION_NUM and alias lua_pushinteger
src/login.c: Whitespace
src/journal.c: Make sure we get a valid timeout
src/login: Add header file (login.h)
src/login.c: Add support for login monitoring
README: misc fixes