remove use of flags in autoconf and add pthread to libraries
fix variadic arguments
move handle common method to UV::Handle module and include it in handle sub-class
call mrb_uv_gc in finalization
don't use handle module in FS
add UV.guess_handle
add UV::Semaphore
don't use librt in darwin
Move uv handles code to handle.c .
Separate uv_context to reduce memory use.
Clear DATA_PTR of FS when close.
Implement correct mrb_uv_fs_fd.
Move thread codes to src/thread.c .
Implement dynamic library methods.
Implement exepath, cwd, chdir.
Remove unnecessary check.
Implement alive?, stop, update_time, backend_fd, backend_timeout method to UV::Loop.
Implement UV.loadavg .
Move UV::FS to src/fs.c .
Remove implemented functions from TODO.